The Constitution, Foreign Wars and the Tenth Amendment

Evaluating Trump’s Continued Arms for Ukraine and Israel

When a sitting U.S. president decides to commit tens of billions of dollars’ worth of weapons to foreign conflicts, ordinary citizens seldom ask whether such largesse has a constitutional basis. But what if the Constitution delegated no such authority to the executive? President Donald Trump’s decisions in 2025 to resume arms shipments to Ukraine and to release large bombs and munitions to Israel are therefore more than just foreign‐policy controversies. They challenge the constitutional structure itself. So how would the Founders evaluate the Trump administration’s approach juxtaposed with the federal government designed in 1787.

Enumerated powers and the Tenth Amendment

Among Congress’s powers listed in Article I, Section 8 of the Constitution are the powers to “pay the debts and provide for the common defense and general welfare,” to declare war and raise armies, and to make laws “necessary and proper” for executing those powers. There is no clause authorizing Congress to fund or arm foreign governments to prosecute wars in which the United States is not a belligerent. James Madison explained in Federalist No. 45 that the powers delegated to the federal government are “few and defined.” The delegated powers relate principally to “external objects, as war, peace, negotiation, and foreign commerce;” the states retain authority over “the lives, liberties, and properties of the people.” In other words, the Constitution authorized the federal government to provide for national defense and to wage war when necessary, but not to become the perpetual armorer for other nations.

The Bill of Rights codifies this principle with the Tenth Amendment. Thomas Jefferson invoked this principle in his 1791 opinion against chartering a national bank. To “take a single step beyond the boundaries thus specially drawn around the powers of Congress,” he warned, “is to take possession of a boundless field of power, no longer susceptible of any definition.” Jefferson feared that if Congress could infer powers from vague phrases like “general welfare,” then “all the preceding and subsequent enumerations of power” would become “completely useless.” He insisted that the general-welfare language allowed Congress only to lay taxes for the enumerated purposes, not to wield a general police power.

The Trump administration’s arms-for-allies programs

In July 2025 President Trump announced a “weapons purchasing scheme” whereby European allies would donate Patriot missile batteries and other equipment to Ukraine and the U.S. would sell those allies replacements. Under the plan, Patriot systems were expected to arrive in Ukraine “within days,” yet American officials admitted that the scheme remained largely an unfleshed framework. Europe would foot the bill for the donated equipment while U.S. arms manufacturers would profit from replenishing their stockpiles. This arrangement appealed to Trump’s political base by making Europeans “pay” for Ukraine’s defense.

From a constitutional perspective, however, the plan is problematic. Congress’s enumerated powers include raising and supporting armies and providing for the “common defense” of the United States, not arming foreign armies. Defenders might argue that Russia’s invasion of Ukraine threatens global stability and thus implicates U.S. national security. But even if one accepts that the fate of Ukraine indirectly affects American interests, the enumerated powers restrict Congress to means necessary for America’s defense. Nothing in Article I authorizes Congress to conscript the American taxpayer into financing a proxy war in Eastern Europe. Jefferson rejected the interpretation that Congress may do anything that might promote the general welfare of humanity. If no U.S. declaration of war has been issued and America itself is not under attack, there is no enumerated power to funnel weapons to a foreign government.

The plan also invites entanglement: once the United States supplies an ally with advanced missile systems, its credibility becomes tied to the ally’s success. As John Quincy Adams warned in 1821, America “goes not abroad, in search of monsters to destroy.” She is “the champion and vindicator only of her own.” Adams cautioned that once America did so, her “fundamental maxims” would change from liberty to force.

The Trump administration’s support for Israel has been even more direct. On Jan. 25 2025 Trump instructed the U.S. military to release 2,000‑pound bombs that the Biden administration had refused to deliver. Trump justified the decision by saying that Israel had paid for the bombs and “they’ve been waiting for them for a long time.” The bombs had been withheld because of their potential to cause indiscriminate destruction; a single 2,000‑pound bomb can rip through thick concrete and create a wide blast radius. Humanitarian advocates had urged an arms embargo amid Israel’s assault on Gaza, which killed more than 47,000 people and caused widespread hunger and displacement. Israel denies accusations of genocide and war crimes, but a U.N. special rapporteur reported to the Human Rights Council that there were “reasonable grounds to believe that the threshold…of genocide” in Gaza had been met. In February 2025 the Trump administration followed up with an emergency approval of nearly $3 billion in bombs for Israel. The sale bypassed normal congressional review and used emergency authorities, the second such emergency action that month.

Under the Constitution, only Congress may declare war. Yet the United States is effectively supplying the means for Israel’s war in Gaza without any congressional debate over American involvement. Even if one believes that Israel has a right to self‑defense, the question for constitutionalists is whether the federal government may finance and supply weapons for another nation’s military campaign as an ordinary matter of foreign relations. The text of Article I does not authorize Congress to provide bombs to allies to prosecute wars unconnected to America’s own defense. Therefore, the appropriation of funds for these weapons violates the Tenth Amendment’s reservation of undelegated powers.

Tariffs, proxies and the “general welfare”

Trump’s plan also threatens another enumerated power: the power to regulate commerce. Article I empowers Congress “To regulate commerce with foreign nations.” But using trade sanctions or tariffs as a tool to coerce foreign nations to adopt specific foreign policies is far removed from the original understanding of regulating commerce. Threatening to impose 100 percent tariffs on any country that buys Russian oil if Moscow does not reach a ceasefire turns the commerce power into an instrument of foreign policy—precisely the sort of expansion Jefferson warned would convert the general‐welfare clause into a boundless power.

Similarly, Article I authorizes Congress to “raise and support Armies” but specifies that no appropriation for this purpose shall be for more than two years. The framers inserted this limitation to prevent standing armies from becoming instruments of tyranny. If the federal government may indefinitely support foreign armies, this temporal limitation becomes meaningless. The enumerated purpose of providing for the “common defense” cannot be stretched to include the defense of every foreign nation that faces aggression.

Founders’ warnings against foreign entanglements

In his 1796 Farewell Address, George Washington admonished Americans to avoid intertwining their destiny with that of other countries. He asked: “Why…entangle our peace and prosperity in the toils of European ambition, rivalship, interest, humor or caprice?” Washington declared that “it is our true policy to steer clear of permanent alliances with any portion of the foreign world.”

Thomas Jefferson echoed this sentiment in his first inaugural address. Among what he called “essential principles of our Government” were “peace, commerce, and honest friendship with all nations, entangling alliances with none.” He also urged a “wise and frugal government, which shall restrain men from injuring one another” yet “shall not take from the mouth of labor the bread it has earned.” The principle of nonintervention is not a pacifist ideal; it flows from a recognition that involvement in foreign wars inevitably expands federal power and requires taxation and regulation.

John Quincy Adams, speaking on the 4th of July 1821, took Washington and Jefferson’s warnings a step further. He described America as a friend to freedom everywhere but cautioned that she “goes not abroad in search of monsters to destroy.” If America once “enlist[s] under other banners,” Adams warned, she will be caught “in all the wars of interest and intrigue…[and] the fundamental maxims of her policy would insensibly change from liberty to force.”

Consequences of ignoring constitutional limits

Supporters of foreign aid often point to humanitarian concerns. Russia’s invasion has caused immense suffering in Ukraine, and Hamas’s attack on Israel in 2023 and Israel’s subsequent assault on Gaza have killed tens of thousands. But genuine compassion does not justify the federal government’s ignoring the constitutional framework. If Congress can spend billions of dollars arming foreign nations whenever a humanitarian crisis arises, what remains of the promise that undelegated powers are reserved to the states or the people?

There are also practical dangers. The Trump administration’s policy of threatening massive tariffs to coerce other countries could ignite trade wars, harming American consumers and manufacturers. The Patriot missiles sent abroad may never be returned; European allies may expect America to replace them, straining the U.S. industrial base. Arming Ukraine could provoke escalation with nuclear‑armed Russia. Supplying thousands of bombs to Israel deepens America’s entanglement in the Middle East. Observant economists point out that the first law of economics is scarcity and that the first law of politics is to ignore the first law of economics. By ignoring constitutional limits, politicians also ignore economic limits.

Toward constitutional fidelity

What might a constitutionally faithful approach to international conflicts look like? First, Congress should recognize that its powers are limited to those directly affecting the United States. If Americans want to support Ukraine or Israel, they are free to do so privately. States could also decide, within their own constitutional frameworks, to provide humanitarian aid. But the federal government has no enumerated power to serve as the world’s arsenal.

Second, when true national defense is implicated, Congress should follow the proper procedure: debate, vote and, if necessary, declare war. As Madison observed in 1793, “the power of declaring war…ought to be fully and exclusively vested in the legislature” because the executive is the branch “most interested in war, and most prone to it.”

Third, the United States should return to Washington and Jefferson’s counsel of non-permanent alliances. Temporary alignments in emergencies are sometimes necessary, but permanent entanglements lead to endless commitments and encourage foreign governments to rely on American arms instead of pursuing their own defense or negotiating peace.

A constitution of enumerated powers is more than a parchment barrier; it is the guardrail that preserves a free republic. The Trump administration’s decisions to resume arms shipments to Ukraine and provide munitions to Israel cannot be justified by any enumerated power. They are precisely the sort of “boundless field of power” Jefferson warned against. They also run contrary to the Founders’ repeated warnings to avoid entangling alliances and foreign wars.

Ignoring the Tenth Amendment to fund foreign wars not only erodes constitutional limits but also sets precedents that future presidents can exploit. If we accept the argument that the general welfare authorizes arming allies today, nothing prevents a president from using the same rationale to police internal affairs tomorrow. In the end, constitutional government requires the humility to recognize that, however compelling a cause may seem, the federal government may act only within its delegated authority. As Adams urged Americans in 1821, let us recommend freedom abroad by the “sympathy of our example,” not by sending missiles and bombs. Only by honoring the limits the Founders set can America remain both free at home and a moral force abroad.