The Interstate Commerce Clause

The Congress shall have Power . . . To regulate Commerce . . . among the several States. . . .

—Randy E. Barnett

Introduction

The Interstate Commerce Clause operates both as a power delegated to Congress and as a constraint on state legislation. The clause is one of the two greatest sources of federal power along with Congress’s power to tax. Its three operative terms are “commerce,” “to regulate,” and “among the several states.” The Supreme Court has decided many cases over the years interpreting these three terms. This provision also operates as the so-called Dormant Commerce Clause, which imposes an external restraint on state legislation that may impede or intrude on interstate commerce.

The Original Meaning of “Commerce”

Justice Clarence Thomas’s concurring opinion in United States v. Lopez (1995) provides evidence of the original meaning of “commerce.”¹ “At the time the original Constitution was ratified,” he wrote, “‘commerce’ consisted of selling, buying, and bartering, as well as transporting for these purposes.”² He further noted that the etymology of the word “commerce” meant “with merchandise.” Although some scholars have disputed this definition,³ it has been confirmed by others, including the present author.⁴

Perhaps the most important evidence of the more limited original meaning of “commerce” is how frequently “commerce” was listed alongside other productive activities such as “manufacturing” and “agriculture.” At the Constitutional Convention, James Madison of Virginia proposed to grant Congress the power “[t]o establish public institutions, rewards, and immunities for the promotion of agriculture, commerce, trades and manufactures.”⁵

At the Massachusetts ratification convention, Thomas Dawes, a prominent revolutionary and legislator, observed that “[w]e have suffered . . . for want of such authority in the federal head. This will be evident if we take a short view of our agriculture, commerce, and manufactures.”⁶ At the New York ratification convention, Governor George Clinton referred to “[t]he situation of [each state’s] commerce, its agriculture, and the system of its resources.”⁷

Such evidence consistently suggests that not all economic or gainful activity was considered “commerce.” And this evidence is inconsistent with the claim that noneconomic activity was considered “commerce.” Rather, commerce was the activity of buying, selling, trading, and moving the goods produced by such activities as manufacturing and agriculture. Given that commerce involves movement rather than production, the activity of transportation itself—often called “navigation” or the “carrying trade”—was also included in the original meaning of “commerce.”

The Original Meaning of “to Regulate”

The core meaning of “to regulate” is to make regular—that is, to specify how an activity should be done, not whether it can be done. A pure regulation specifies that “if you want to do X, this is how you do it.” Did the power “to regulate” commerce also include the power to prohibit it? The Migration or Importation Clause suggests it did.⁸ The Commerce Clause gave Congress the power to regulate—that is, “make regular”—the “Migration or Importation” of slaves from other nations. In other words, Congress could say how the slave trade should be conducted, which it did through the Slave Trade Act of 1794.⁹ But because the Migration or Importation Clause expressly limited Congress’s power to “prohibit[]” the slave trade altogether until 1808, this suggests that the power to “regulate” commerce included some power to prohibit it as well.¹⁰

James Madison once invoked the concept of a “prohibitory regulation” of trade in describing a measure adopted by Virginia before the Constitution. That law was enacted to induce a reciprocal easing of trade barriers by Great Britain. Madison observed that, in response to complaints against “the monopolizing navigation laws of [Great Britain], particularly in the trade between the U. S. & the British W. Indies, [Virginia] deliberated . . . on the experiment of forcing a reciprocity by prohibitory regulations of her own.”¹¹ Thus it was contemplated that, at least for some purposes, a regulation of trade could take the form of a prohibition.

The U.S. Supreme Court did not affirm this interpretation of “to regulate” until Champion v. Ames (1903).¹² By a vote of 5 to 4, the Court upheld a congressional ban on the interstate transportation of lottery tickets. Writing for the majority, Justice John Marshall Harlan reasoned that Congress, like the states, “may prohibit the carrying of lottery tickets from one state to another” in order to “guard[] the people of the United States against the ‘widespread pestilence of lotteries’ and to protect the commerce which concerns all the states.”¹³ In essence, Harlan reasoned that Congress had the same plenary “police power” over interstate commerce that states have over activities within their borders.

The view that Congress’s power “to regulate” interstate commerce includes the power to prohibit commerce remains good law. By the same token, however, just as the Fourteenth Amendment’s Due Process of Law Clause restricts the police power of states, the Fifth Amendment’s Due Process of Law Clause may likewise limit Congress’s power to regulate or prohibit interstate commerce.

The Original Meaning of “Among the Several States”

The most obvious meaning of commerce “among the several states” is activity that is taking place between one or more states and another one or more states. For example, in 1791, Treasury Secretary Alexander Hamilton wrote an opinion concluding that the Bank of the United States was constitutional. Hamilton described “the province of the federal government” under the Commerce Clause as the power to regulate “the trade with foreign countries, or . . . between the States, or with the Indian Tribes.”¹⁴

Constitutional historian William Crosskey advanced the most prominent objection to this view. Crosskey contended that the “natural meaning” of “among the several states” includes all commerce occurring within any state.¹⁵ He read the clause to empower Congress to regulate commerce “with the people of foreign nations, commerce with the people of the Indian tribes, and commerce among the people of the several states.”¹⁶ Under this reading, “the clause covered the societal internal commerce of the country, plus its two kinds of societally external commerce. . . .”¹⁷

But Crosskey’s method of establishing “original meaning” was distorted. He deliberately excluded any evidence of usage during the framing or ratifying of the Constitution. Instead, his “samples of word-usage and juristic and political discussion” were all “drawn . . . from sources not connected with the Constitution.”¹⁸ Contemporary originalist methodology, however, identifies the meaning of words by reference to the context in which these words were used at the time they were adopted. Such contextual evidence of word and phrase usage is not susceptible to the type of “natural suspicions” for which Crosskey professed concern when he excluded statements made during the drafting and ratifying of the Constitution. Crosskey’s skewed methodology is not consistent with now well-established principles of constitutional originalism.

The first Supreme Court case to interpret the Interstate Commerce Clause was Gibbons v. Ogden (1824). It decided that the power to regulate “commerce” included the power to regulate navigation or the carrying trade.¹⁹ The Federal Coasting Act of 1793 gave the plaintiffs a monopoly license to carry passengers on boats from New York to New Jersey. The Court held that this statute was a proper exercise of the power to regulate commerce among the several states.

Under the original meaning of “commerce,” Gibbons was an easy case. Congress clearly had power over the activity of interstate navigation. In this case, the activity being regulated took place between one state and another. Congress was merely regulating navigation, not prohibiting it. But Chief Justice John Marshall’s majority opinion contained some capacious language that later led to an expansionist reading of the clause: “This power,” for example, “like all others vested in Congress, is complete in itself, may be exercised to its utmost extent, and acknowledges no limitations, other than are prescribed in the Constitution.”²⁰

This passage has led some jurists and scholars to contend that the only restrictions on the powers of Congress must be based on one of the express prohibitions, such as those in the Bill of Rights, and not on the limited meaning of the terms of the power itself. But Marshall recognized an inherent limit to this power over “commerce.” He reasoned that “[t]he enumeration” of powers over three types of commerce—with foreign nations, between states, and with Indian tribes—“presupposes something not enumerated, and that something, if we regard the language or the subject of the sentence, must be the exclusively internal commerce of a State.” With this limit in mind, he considered the meaning of the particular words in the clause.

The meaning of “commerce.” Commerce, Marshall wrote, is more than “traffic”—that is, more than mere trade. This claim is well supported by evidence of original meaning. But Marshall also referred repeatedly to the seemingly broader concept of “commercial intercourse.” Professor Jack Balkin has claimed that the term “intercourse” is synonymous with “interaction.”²¹ When the Constitution was framed, however, “intercourse”—like “commerce”—referred to the movement of something from one place to another. Intellectual intercourse, for example, concerned the transmission of ideas between persons. By qualifying “intercourse” with “commercial,” Marshall was not expanding the meaning of commerce. He was restricting the scope of the intercourse that fell within congressional power.

The meaning of “to regulate.” Marshall defined “the power to regulate” as the power “to prescribe the rule by which commerce is to be governed.”²² In other words, Congress had the power to establish the manner in which commerce is to be conducted.

The meaning of “among the several states.” Finally, Marshall addressed the meaning of “among the several states.” He affirmed that Congress’s claim over navigation between two states “implies no claim of a direct power to regulate the purely internal commerce of a State or to act directly on its system of police,”²³ but he adopted a potentially expansive interpretation of “among.” “Comprehensive as the word ‘among’ is,” he wrote, “it may very properly be restricted to that commerce which concerns more States than one.”²⁴ Marshall then offered an even more expansive definition of “among” as “intermingled with.” His statement that “[a] thing which is among others is intermingled with them” has led some scholars like Crosskey to contend that “among” meant amidst or even within a state.²⁵

Yet Marshall himself rejected this reading. He insisted, as noted, that “[t]he enumeration presupposes something not enumerated; and that something, if we regard the language or the subject of the sentence, must be the exclusively internal commerce of a State.” Purely local activities therefore remained outside of the reach of Congress.

The Close Relationship Between the Commerce and Necessary and Proper Clauses

Article I, Section 8, Clause 18 delegates to Congress the power “[t]o make all Laws which shall be necessary and proper for carrying into Execution the foregoing Powers, and all other Powers vested by this Constitution in the Government of the United States, or in any Department or Officer thereof.” (See Essay No. 66.) In Gibbons v. Ogden, Chief Justice Marshall noted that there may be some “internal concerns” of a state with which it may be “necessary [for Congress] to interfere . . . for the purpose of executing some of the general powers of the government.”²⁶ Thus, even if these local activities are neither commerce nor interstate, Congress may still be able to regulate them if such a law is necessary and proper to execute its power over interstate commerce.

Five years before Gibbons, the Court decided McCulloch v. Maryland (1819).²⁷ Marshall, writing for the Court, offered an important test to understand the Necessary and Proper Clause: “Let the end be legitimate, let it be within the scope of the constitution, and all means which are appropriate, which are plainly adapted to that end, which are not prohibited, but consist with the letter and spirit of the constitution, are constitutional.”²⁸ During the twentieth century, most of the expansion of Congress’s powers under the Commerce Clause came not from expanding the meaning of “commerce,” but from expanding the meaning of “necessary and proper” in the Necessary and Proper Clause.

In McCulloch, however, Marshall articulated three limiting principles on how far the Necessary and Proper Clause reached. First, Congress cannot “adopt measures which are prohibited by the constitution.”²⁹ Second, a law must be “really calculated to effect any of the objects intrusted to the Government.”³⁰ This suggests that Congress must have some demonstrable reason for regulating a particular activity as a means of carrying into execution one of its enumerated powers.

Third, Congress cannot, “under the pretext of executing its powers, pass laws for the accomplishment of objects not entrusted to the government.”³¹ In such cases, Marshall wrote, “it would become the painful duty of this tribunal . . . to say that such an act was not the law of the land.”³² It follows that Congress can regulate a local activity only if its purpose for doing so comports with its delegated power to regulate commerce between the states and the regulation is plainly adapted to that purpose.

The first Supreme Court case to declare unconstitutional a regulation of interstate commerce was United States v. Dewitt (1869).³³ Federal law prohibited the sale of “illuminating oil” anywhere in the United States, including all local sales. Chief Justice Salmon P. Chase’s majority opinion tracked the reasoning of Gibbons. Chase explained that the “express grant of power to regulate commerce among the states has always been understood as limited by its terms, and as a virtual denial of any power to interfere with the internal trade and business of the separate states.”³⁴ Chase, however, also acknowledged an exception to this rule premised on the Necessary and Proper Clause: Congress could regulate such internal trade “as a necessary and proper means for carrying into execution some other power expressly granted or vested.”³⁵

But Chase then rejected the argument that such a ban was a necessary and proper means of exercising Congress’s power to tax. Rather, the federal ban was not an appropriate and plainly adapted means for carrying into execution “the power of laying and collecting taxes.”³⁶ Here, Chase paraphrased Chief Justice Marshall’s opinion in McCulloch v. Maryland.37 Dewitt highlights the close connection between the scope of the interstate commerce power and the scope of the Necessary and Proper Clause.

The Progressive-Era Court

Following Gibbons and Dewitt, the Supreme Court had little occasion to investigate the breadth of the federal commerce power. That would change during the Progressive Era in the late nineteenth century with the growth of national economic legislation. United States v. E.C. Knight Co. (1895) held that the Sherman Antitrust Act could not constitutionally be applied to monopolies in manufacturing because the word “commerce” did not embrace manufacturing.³⁷ Moreover, any effect manufacturing may have on commerce was merely “indirect” and could not be reached under the Necessary and Proper Clause.

This qualitative distinction between manufacturing and commerce held for forty years, although the Court was generally deferential in upholding federal regulatory legislation. For example, several cases established what later came to be called the “jurisdictional element” test.³⁸ Under this test, Congress can regulate or prohibit activity that employs any item that traveled across state lines regardless of whether the activity being regulated was itself commerce, or even economic.

The last restrictive applications of the commerce power by the Court came in 1935 and 1936. A.L.A. Schechter Poultry Corp. v. United States (1935) declared unconstitutional the National Industrial Recovery Act, which was the centerpiece of the Roosevelt Administration’s New Deal legislation.³⁹ The Court held that this statute impermissibly regulated goods after their interstate transportation or movement had come to rest.⁴⁰ The following year, Carter v. Carter Coal Co. (1936) held that Congress could not regulate goods before their interstate transportation had begun.⁴¹ In both cases, the Court found that the effect of the activity being regulated on interstate commerce was too “indirect” to be within Congress’s Necessary and Proper Clause power to reach activity that was itself “commerce . . . among the several states.”

The New Deal-Era Court

The law would start to shift one year later. NLRB v. Jones & Laughlin Steel Corp. (1937) upheld the National Labor Relations Act’s regulation of factory working conditions.⁴² This case did not squarely reject the direct-indirect test. Under the Necessary and Proper Clause, Congress could not reach activities that had only an “indirect and remote” effect on interstate commerce. But Congress could reach activities that had a “close and intimate effect” on interstate commerce. An industry organized on a national level, like the steel company, had such an effect. The Court also acknowledged a principle that was reminiscent of Chief Justice Marshall’s limit in Gibbons: “The authority of the federal government may not be pushed to such an extreme as to destroy the distinction, which the commerce clause itself establishes, between commerce ‘among the several States’ and the internal concerns of a State.”⁴³ The Court stressed that the “distinction between what is national and what is local in the activities of commerce is vital to the maintenance of our federal system.”⁴⁴

Four years later, however, in United States v. Darby (1941), the Court abandoned any effort to draw such a line between what is national and what is local.⁴⁵ Darby rejected the direct-indirect test in favor of what came to be known as the “substantial effects” doctrine. Under this test, Congress has “the power . . . to regulate . . . activities intrastate which have a substantial effect on the commerce or the exercise of the Congressional power over it.”⁴⁶ To justify this doctrine, the Court relied, not on the Commerce Clause case of Gibbons v. Ogden, but on the Necessary and Proper Clause standard articulated by Marshall in McCulloch v. Maryland: Congress could regulate “those activities intrastate which so affect interstate commerce . . . as to make regulation of them appropriate means to the attainment of a legitimate end.”⁴⁷

This passage is revealing. Contrary to how Darby is often read, this case did not expand the meaning of “commerce” beyond its original meaning. Instead, the Court held that Congress’s power “is not confined to the regulation of commerce among the states.”⁴⁸ Under what clause, then, could Congress regulate local activity? The Court cited McCulloch v. Maryland as authority for this expansive power. Darby signals that the “substantial effects doctrine” is a product of an expansion of the Necessary and Proper Clause, not an expansion of the original meaning of “commerce.”

Yet Darby was not entirely faithful to everything Chief Justice Marshall held in McCulloch. In particular, Darby rejected Marshall’s limiting principle that “pretextual” laws “for the accomplishment of objects not entrusted to the government” were beyond that power.⁴⁹ Rather, Darby held that “[t]he motive and purpose of a regulation of interstate commerce are matters for the legislative judgment upon the exercise of which the Constitution places no restriction, and over which the courts are given no control.”⁵⁰ The Court opined that “[w]hatever [Congress’s] motive and purpose, regulations of commerce which do not infringe some constitutional prohibition are within the plenary power conferred on Congress by the Commerce Clause.”⁵¹ In other words, without saying so, Darby quietly reversed one of McCulloch’s limits on the Necessary and Proper Clause.

The reasoning of Wickard v. Filburn (1942) further shows how the New Deal Court was not expanding the meaning of “commerce” but was expanding the scope of the Necessary and Proper Clause.⁵² The Agricultural Adjustment Act sought to help farmers by raising the market price of wheat. The law did so by limiting the amount of wheat a farmer could grow and market.⁵³ Wickard upheld the constitutionality of this law. The original meaning of “commerce” did not include the activity of agriculture and Wickard did not deny this meaning. Instead, it held that if an “activity be local, and though it may not be regarded as commerce, it may still, whatever its nature, be reached by Congress if [that activity] exerts a substantial economic effect on interstate commerce. . . .”⁵⁴ In this way, Wickard stayed within the original meaning of “commerce” while expansively interpreting the Necessary and Proper Clause.

Wickard further held that, to assess whether an activity has a substantial effect on interstate commerce, one should consider the effect of all incidences of the activity. This rule has come to be known as the “aggregation principle.”

Along with the “jurisdictional element” test, both the substantial effects doctrine and the aggregation principle remain good law. The Court has used all three tests to approve wider federal criminal legislation as well as major social reforms such as the Civil Rights Act of 1964.⁵⁵

The Rehnquist Court

United States v. Lopez (1995) and United States v. Morrison (2000) found a limit to the substantial effects doctrine by introducing a distinction between economic and noneconomic local activity.⁵⁶ In Lopez, the Court held that Congress could regulate local economic activity that, in the aggregate, had a substantial effect on interstate commerce and its regulation.⁵⁷ But local noneconomic activity was outside Congress’s power regardless of its aggregate effect on interstate commerce.⁵⁸ Furthermore, unlike economic activity, noneconomic activity could not be aggregated to show a substantial effect on commerce.⁵⁹ Moreover, Chief Justice William H. Rehnquist asserted that it was the Court’s independent duty to determine whether a regulated activity was economic in nature.61 His opinion based these limits, not on the original meaning of the Commerce Clause, but on “first principles” and post-New Deal precedents.

In Morrison, Chief Justice Rehnquist stated that “thus far in our Nation’s history our cases have upheld Commerce Clause regulation of intrastate activity only where that activity is economic in nature.”⁶⁰ Therefore, by drawing this line, no post-New Deal case needed to be reversed. Instead, the Rehnquist Court adopted a stance that can be described as “this far and no farther without a judicially administrable limiting principle.”

Five years later, however, the Rehnquist Court seemed to pivot in Gonzales v. Raich (2005). The Court held that the federal Controlled Substances Act (CSA) properly reached locally home-grown marijuana notwithstanding a California law that legalized marijuana for medicinal use.⁶¹ The vote in Raich was 6 to 3. In one sense, Raich stayed within the economic-noneconomic line drawn by Lopez and Morrison. The majority relied on Webster’s Third New International Dictionary to hold that “economics” refers to “the production, distribution, and consumption of commodities.”⁶² Therefore, the Court concluded that, under Lopez and Morrison, Congress could reach this local activity under the substantial effects doctrine and aggregation principle.

In Raich, both the majority opinion and Justice Antonin Scalia’s concurrence also relied on a statement made in passing in Lopez. Lopez left the door open for Congress to regulate even noneconomic local activity if such regulation is “an essential part of a larger regulation of economic activity, in which the regulatory scheme could be undercut unless the intrastate activity were regulated.”⁶³ In his concurring opinion in Raich, Justice Scalia correctly characterized this power as based on the Necessary and Proper Clause rather than the Commerce Clause.⁶⁴ Scalia would then have used deferential “rational basis” scrutiny to review Congress’s claim that the regulation of intrastate activity—whether economic or noneconomic—was an essential part of a broader regulatory scheme.

The Roberts Court

Raich did not signal the end of the Court’s attempt to find some limit to Congress’s power to regulate interstate commerce. National Federation of Independent Business v. Sebelius (2012) found another.⁶⁵ Unlike Lopez, Morrison, and Raich, NFIB did not involve the substantial effects doctrine, which expansively reads the “necessary” part of the Necessary and Proper Clause. Instead, NFIB raised the question of whether compelling persons to engage in economic activity by requiring them to purchase health insurance from a private company was a “proper” exercise of Congress’s power “to regulate.” Chief Justice Roberts’s controlling opinion observed that “[t]he Framers gave Congress the power to regulate commerce, not to compel it, and for over 200 years both our decisions and Congress’s actions have reflected this understanding.”⁶⁶ The power to compel, he wrote, “would give Congress the same license to regulate what we do not do, fundamentally changing the relation between the citizen and the Federal Government.”69 The individual insurance mandate exceeded Congress’s power under the Necessary and Proper Clause: “Laws that undermine the structure of government established by the Constitution . . . are not “consist[ent] with the letter and spirit of the constitution.” Here, Roberts quoted McCulloch: Such laws “are not ‘proper [means] for carrying into Execution’ Congress’s enumerated powers.”

The Dormant Commerce Clause

The Interstate Commerce Clause has a second constitutional role. This provision acts as an external restraint on state legislation that may impede or intrude upon interstate commerce. This principle is known as the Dormant Commerce Clause, which traces to Willson v. Black-Bird Creek Marsh Co. (1829).⁶⁷ Chief Justice John Marshall wrote that a state law placing a dam across a creek was not “repugnant to [Congress’s] power to regulate commerce in its dormant state, or as being in conflict with any law passed on the subject.”⁶⁸

The phrase “commerce in its dormant state” is confusing. Chief Justice Marshall was not referring to commerce that was dormant. Rather, he was referring to when Congress has not exercised its Commerce power. In other words, Marshall was referring to Congress’s unexercised or “dormant” “power to regulate commerce.” Can states exercise power over intrastate commerce that Congress has chosen not to regulate, or is Congress’s power exclusive so that its failure to regulate means that activity must go unregulated by the states as well?

Since the nineteenth century, the courts have vacillated on the scope of the Dormant Commerce Clause doctrine.⁶⁹

1. 514 U.S. 549 (1995). ↩︎
2. Id. at 585. ↩︎
3. Grant S. Nelson & Robert J. Pushaw, Jr., Rethinking the Commerce Clause: Applying First Principles to Uphold Federal Commercial Regulations but Preserve State Control over Social Issues, 85 Iowa L. Rev. 1 (1999); Jack M. Balkin, Commerce, 109 Mich. L. Rev. 1 (2010). ↩︎
4. Randy E. Barnett, The Original Meaning of the Commerce Clause, 68 U. Chi. L. Rev. 101 (2001); Randy E. Barnett, Jack Balkin’s Interaction Theory of “Commerce,” 2012 U. Ill. L. Rev. 623 (2012); Robert G. Natelson & David Kopel, Commerce in the Commerce Clause: A Response to Jack Balkin, 109 Mich. L. Rev. First Impressions 55 (2010). ↩︎
5. 2 Farrand’s 322. ↩︎
6. 2 Elliot’s 57. ↩︎
7. Id. at 261. ↩︎
8. Art. I, § 9, cl. 1. ↩︎
9. 1 Stat. 347. ↩︎
10. 2 Stat. 426. ↩︎
11. James Madison, Letter to Joseph C. Cabell, Sept. 18, 1828, https://perma.cc/LFW9-QEK6. ↩︎
12. 188 U.S. 321 (1903). ↩︎
13. Id. at 357. ↩︎
14. Alexander Hamilton, Final Version of an Opinion on the Constitutionality of an Act to Establish a Bank, (Feb. 23, 1791) (emphasis added), https://perma.cc/7NDR-HAK9. ↩︎
15. William Winslow Crosskey, 1 Politics and the Constitution in the History of the United States 50–83 (1953). ↩︎
16. Id. at 77. ↩︎
17. Id. ↩︎
18. Id. at 5. ↩︎
19. 22 U.S. (9 Wheat.) 1 (1824). ↩︎
20. Id. at 196 (emphasis added). ↩︎
21. Balkin, supra at 15. ↩︎
22. Gibbons, 22 U.S. (9 Wheat.) at 196. ↩︎
23. Id. at 204. ↩︎
24. Id. at 194 (emphasis added). ↩︎
25. Walton H. Hamilton & Douglass Adair, The Power to Govern: The Constitution—Then and Now 141–42 (1937). ↩︎
26. Gibbons, 22 U.S. (9 Wheat.) at 195 (emphasis added). ↩︎
27. 17 U.S. 316 (4 Wheat.) (1819). ↩︎
28. Id. at 421. ↩︎
29. Id. at 423. ↩︎
30. Id. (emphasis added). ↩︎
31. Id. (emphasis added). ↩︎
32. Id. ↩︎
33. 76 U.S. 41 (1869). ↩︎
34. Id. at 44. ↩︎
35. Id. ↩︎
36. Id. ↩︎
37. 156 U.S. 1 (1895). ↩︎
38. Hipolite Egg Co. v. United States, 220 U.S. 45 (1911); Hoke v. United States, 227 U.S. 308 (1913); Caminetti v. United States, 242 U.S. 470 (1917). ↩︎
39. 295 U.S. 495 (1935). ↩︎
40. Id. at 548–50. ↩︎
41. 298 U.S. 238 (1936). ↩︎
42. 301 U.S. 1 (1937). ↩︎
43. Id. at 30. ↩︎
44. Id. ↩︎
45. 312 U.S. 100 (1941). ↩︎
46. Id. at 119–20. ↩︎
47. Id. at 118. ↩︎
48. Id. ↩︎
49. Id. at 121. ↩︎
50. Id. at 115. ↩︎
51. Id. (emphasis added) ↩︎
52. 317 U.S. 111 (1942). ↩︎
53. Id. at 113. ↩︎
54. Id. at 125 (emphasis added). ↩︎
55. Heart of Atlanta Motel, Inc. v. United States, 379 U.S. 241 (1964); Katzenbach v. McClung, 379 U.S. 294 (1964). ↩︎
56. 514 U.S. 549 (1995); 529 U.S. 598 (2000). ↩︎
57. Lopez, 514 U.S. at 565–68. ↩︎
58. Id. ↩︎
59. Id. ↩︎
60. 514 U.S. at 613. ↩︎
61. 545 U.S. 1 (2005). ↩︎
62. Id. at 25. ↩︎
63. Lopez, 514 U.S. at 561. ↩︎
64. Raich, 545 U.S. at 38. ↩︎
65. 567 U.S. 519 (2012). ↩︎
66. Id. at 555 (emphasis removed). ↩︎
67. 27 U.S. (2 Pet.) 245 (1829). ↩︎
68. Id. at 252 (emphasis added) ↩︎
69. Nat’l Pork Producers Council v. Ross, 598 U.S. 356 (2023). ↩︎