Could the federal government ban people from drinking coffee?

Question

Which amendment does this statement violate?

The federal government refuses to allow anyone to drink coffee.

Answer 1

None. The federal government is allowed to prohibit coffee drinking under its power to regulate interstate commerce. Prohibition would not have required a constitutional amendment under modern constitutional jurisprudence either. By analogy, this would be no different (constitutionally) than a law prohibiting putting lithium in sodas (something that used to be done in 7 Up) or putting cocaine in sodas (something that used to be done in Coca-Cola).

Conceivably, the law might have to allow a religious exemption in certain circumstances under the 1st Amendment's free exercise clause, but while many faiths prohibit drinking coffee (most notably, offshoots of The Church of Jesus Christ of Latter-day Saints), none of which I am aware require it as a matter of religious doctrine sincerely espoused.

Answer 2

This would almost certainly be within Congress's powers under the Commerce Clause, which has been interpreted quite broadly to encompass virtually anything someone could imagine possibly affecting interstate commerce, even indirectly.

There are two particularly on-point Supreme Court cases: Gonzales v. Raich in 2005 and Wickard v. Filburn in 1942. Gonzales v. Raich held that Congress could prohibit the use of cannabis within a state (even if it never crossed state lines), because it could affect interstate demand for cannabis. It was based in part on Wickard v. Filburn, which held that Congress could prohibit a farmer from growing wheat in excess of specified quotas (even if he never sold that wheat and only used it to feed his own animals), because he would otherwise have to purchase feed, which affects the interstate market for that.

To quote the court in Gonzales:

In both cases, the regulation is squarely within Congress’ commerce power because production of the commodity meant for home consumption, be it wheat or marijuana, has a substantial effect on supply and demand in the national market for that commodity.

The only remaining obstacle would be that the government would have to articulate some rational basis for this law. The rational basis test is the test for the constitutionality of a law in which no fundamental rights or equal-protection violations are at issue. Since banning coffee consumption (probably) doesn't implicate any fundamental rights or discriminate against any protected class of people, it would apply here. It requires 1) that the law advance a legitimate state interest, and 2) that there be a rational connection between that goal and the means by which the law attempts to advance it.

That's not a difficult bar to meet: one possible reason would be that it contains caffeine, an addictive drug that has negative health implications when consumed in excess. Protecting the health of the public would be a legitimate state interest, and restricting the consumption of a harmful substance would advance it.

Answer 3

If Congress bans coffee, the power has to be from some sources found in the constitution. The only conceivable source is the commerce clause. Thus, like other answers, I would focus on whether Congress would exceed its authority under the commerce clause.

Before I get into the details, I would like to clarify a common misconception, especially in the context of the commerce clause: If the US Supreme Court is not willing to declare a law unconstitutional, it is constitutional. This is not true. In other words, Ryan M has given an expansive answer on

Would the Supreme Court declare the law unconstitutional?

but not

Is the law unconstitutional?

Given that the Supreme Court only loosely examines Congress' commerce clause power (see below and Ryan M's answer), we must keep in mind that the answer to the first question can depart significantly from the second.

Background: Supreme Court's Spectrum of Interfering Other Governmental Branches (e.g., Level of Scrutiny)

In a democratic society with multiple government branches interacting with each other, when analyzing constitutional questions, the Supreme Court must consider whether it has the proper role to review and how much it may properly review, via interpreting its role defined in the Constitution. Interactions between governmental branches are about "ambitions counteracting ambitions," not "Supreme Court counteracting ambitions." If the Supreme Court police every single constitutional question in the utmost detail and interpret the constitution as expansive as it can, the government is, at least, close to a dictatorship and all other branches are the unelected Court's subordinates.

The Supreme Court has employed a spectrum of how much it would interfere with other branches of the government's actions. This includes the so-called "level of scrutiny." At one extreme end, the Supreme Court employs strict scrutiny: Federal courts should take close scrutiny at this kind of disputes and actively police whether the government has violated the constitution. Examples of such government actions include opinion-based speech regulation, laws that discriminate based on race, etc. These commonly involve issues that are susceptible to "tyranny of majority," such as fundamental right invasion and discrimination against minority. Federal Courts, less influenced by votes, are in a position to guard these interest.

At the other extreme end, the Supreme Court would deem an issue as not justiciable — in other words, the Supreme Court deems the issue is inappropriate for federal courts to issue opinions, even if there is text on point written in the Constitution. For example, the Supreme Court has never answered the question whether the president can send troops to foreign land without a congressional war declaration, while Article I, Section 8 grants the Congress war declaration power. In fact, this question likely fits into the Court's political question doctrine. Does this mean this is constitutional? Instead, Congress passed the War Powers Act, which, in some sense, can be seen as Congress deeming some prior president's (especially Nixon's) war acts unconstitutional.

Supreme Court on the Commerce Clause

Regarding the commerce clause, the Supreme Court currently employs rational basis test, with some qualifications (noticeably United States v. Lopez, 514 U.S. 549 (1995) and United States v. Morrison, 529 U.S. 598 (2000)). This means that Supreme Court puts commerce clause-related questions closer to the nonjusticiable side of the spectrum. Ryan M's answer is the one that applies rational basis test to the OP's question. As a result, the Supreme Court would unlikely declare this ban unconstitutional. But keep in mind that the Court has never said Congress has unlimited power under the commerce clause.

Who Should Police Congressional Exercise of the Commerce Clause?

Chief Justice Marshall once wrote:

If, as has always been understood, the sovereignty of Congress, though limited to specified objects, is plenary as to those objects, the power over commerce with foreign nations, and among the several States, is vested in Congress as absolutely as it would be in a single government, having in its Constitution the same restrictions on the exercise of the power as are found in the Constitution of the United States. The wisdom and the discretion of Congress, their identity with the people, and the influence which their constituents possess at elections are, in this, as in many other instances, as that, for example, of declaring war, the sole restraints on which they have relied, to secure them from its abuse. They are the restraints on which the people must often rely solely, in all representative governments.

Gibbons v. Ogden, 22 U.S. 1 (1824). Basically, Ogden's view is that the restraint on the Congress' exercise of the commerce clause is not from federal judiciary; it is from the political process. Wickard v. Filburn, 317 U.S. 111 (1942) explained:

[Chief Justice Marshall] made emphatic the embracing and penetrating nature of this power by warning that effective restraints on its exercise must proceed from political, rather than from judicial, processes.

The Supreme Court's current view largely follows the Gibbons line. See e.g., Atlanta Motel v. United States, 379 U.S. 241 (1964) ("The principles which we apply today are those first formulated by Chief Justice Marshall in Gibbons).

According to these opinions, it is likely difficult to find the answer to the OP's question in Court's decisions. The answer likely lies in the political process.

This sort of makes sense, because commerce regulations are complicated and federal courts are poorly equipped to police these regulations. Unlike fundamental right questions, tyranny of majority also rarely finds home in these regulations. (Of course, people have different opinions regarding whether the Supreme Court is too hands-off or not. But as it currently stands, political process should lead to the answer.)

How Does the Political Process Restrain Congress from Abusing Its Commerce Power?

Justice Breyer explained:

... [W]ithin the bounds of the rational, Congress, not the courts, must remain primarily responsible for striking the appropriate state/federal balance. Garcia v. San Antonio Metropolitan Transit Authority, 469 U.S. 528, 552 (1985); ante, at 19-24 ( Souter, J., dissenting); Kimel v. Florida Bd. of Regents, 528 U.S. 94-94, (2000) ( Stevens, J., dissenting) (Framers designed important structural safeguards to ensure that, when Congress legislates, "the normal operation of the legislative process itself would adequately defend state interests from undue infringement"); see also Kramer, Putting the Politics Back into the Political Safeguards of Federalism, 100 Colum. L. Rev. 215 (2000) (focusing on role of political process and political parties in protecting state interests). Congress is institutionally motivated to do so. Its Members represent state and local district interests. They consider the views of state and local officials when they legislate, and they have even developed formal procedures to ensure that such consideration takes place. See, e.g., Unfunded Mandates Reform Act of 1995, Pub.L. 104-4, 109 Stat. 48 (codified in scattered sections of 2 U.S.C.). Moreover, Congress often can better reflect state concerns for autonomy in the details of sophisticated statutory schemes than can the Judiciary, which cannot easily gather the relevant facts and which must apply more general legal rules and categories. See, e.g., 42 U.S.C. § 7543 (b) (Clean Air Act); 33 U.S.C. § 1251 et seq. (Clean Water Act); see also New York v. United States, 505 U.S. 144, 167-168 (1992) (collecting other examples of "cooperative federalism"). Not surprisingly, the bulk of American law is still state law, and overwhelmingly so.

U.S. v. Morrison, 529 U.S. 598 (2000) (Breyer, J., dissenting). Garcia, cited in the passage above, lists some additional examples on how the states would restrain Congress. For example, States have the power to regulate the perhaps most two important aspects of federal election: Districting and voter qualifications; large amount of federal revenue flows to states, meaning that states have effective control over some federal policy execution (keep in mind that an increase in federal taxation generally negatively impacts votes).

So, Is It Constitutional?

According to the above analysis and Supreme Court's previous opinions, the question is more about political process and less about Court opinion analysis. Here, I'm attempting to make a guess on whether the political process would likely restrain Congress from enacting such a law.

The OP provides too little context, and it's difficult to know whether a ban on coffee is truly about "interstate commerce". If coffee has turned out to be something similar to cocaine, then I think it is constitutional. Coffee has an established national market, and to eliminate coffee from the national market, it is necessary to prohibit on the consumption side. Individual states are unlikely able to effectively ban coffee, they would also unlikely oppose this coffee ban. In fact, they may also likely cooperate with the ban: receive federal fund and execute the ban. Given these factors, voters are unlikely voting these Congressmen out of their seats.

Now let's take a different assumption of the facts. Unlike other states, the state of Coffee Fan is plagued with the issue of coffee overdrinking -- 10% of its population drink over one ton of coffee per day. One option is for the state to ban coffee completely because there's no other practical way to administrate the law (for the sake of argument). The point of the law is not about interstate commerce; it is about the market within the state of Coffee Fan alone. In the OP's hypothetical, Congress, instead of the state, plan on enacting such a law. The political process would likely restrain Congress from enacting such a law, because the overwhelming majority of the population in other states still enjoy coffee in benign doses. These state governments also would unlikely cooperate. The 90% of the population in the state of Coffee Fan would also likely oppose, because it becomes more difficult for them to adjust the policy in the future in response to the changes of their local problems.