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. Yet America was founded on the principle that the federal government is one of limited and enumerated powers. Those powers were carefully listed in Article I of the Constitution, and the Tenth Amendment reserves all powers not delegated to the United States to the states or to the people. The Constitution demands that any action taken by the federal government—including funding and arming foreign belligerents—be supported by an enumerated power.
President Donald Trump’s decisions in 2025 to dramatically increase arms shipments to Ukraine and to release large bombs and precision munitions to Israel, despite accusations that Israel’s campaign in Gaza constitutes genocide, 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?
Among Congress’ powers listed in Article I, Section 8 of the Constitution are the power to lay and collect taxes “to pay the debts and provide for the common defense and general welfare,” to borrow money, to regulate commerce, 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,” while the powers remaining with the states are “numerous and indefinite.” 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’ wars.
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. He wrote that the Constitution is founded on the rule that “all powers not delegated to the U.S. by the Constitution…are reserved to the states or to the people.” 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.
In July 2025, President Trump announced what Reuters described as a “weapons purchasing scheme” whereby European allies would donate Patriot missile batteries and other equipment to Ukraine and the United States would sell those allies new American replacements. Trump framed the arrangement as a way to press Russia for a ceasefire: if Moscow did not stop the war, he threatened 100% tariffs on Russian exports. 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’ 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. The constitutional principle is not that Congress may do anything that might promote the general welfare of humanity; Jefferson specifically rejected that interpretation. Under a strict reading, 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.
Economists often remind us that trade‐offs are inescapable. Money and weapons sent overseas are resources not available for domestic defense or to be returned to the taxpayers. The Trump administration’s scheme is not cost‐free simply because European governments are paying for some of the weapons. It requires huge U.S. manufacturing capacity and could lead to backlogs for America’s own defense needs. 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 then-Secretary of State 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,” and knows that if she enlists under other banners she will be “involve[d]…in all the wars of interest and intrigue…which assume the colors and usurp the standard of freedom.” Adams cautioned that once America did so, her “fundamental maxims” would change from liberty to force and she could “become the dictatress of the world.” A policy that openly arms Ukraine while threatening tariffs on any nation buying Russian oil moves the United States closer to the dictatress Adams feared.
The Trump administration’s support for Israel has been even more direct. On January 25, 2025, Trump instructed the U.S. military to release 2,000‑pound bombs that the Joe Biden administration had withheld over concern for civilian casualties in Gaza. Trump justified the decision by saying that Israel had paid for the bombs and “they’ve been waiting for them for a long time.” When asked why he released them, he replied, “because they bought them.” 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 has killed more than 47,000 people and caused widespread hunger and displacement. Israel denies accusations of genocide and war crimes, but a United Nations special rapporteur reported to the Human Rights Council that there were “reasonable grounds to believe that the threshold indicating the commission of the crime of genocide” in Gaza had been met, citing more than 30,000 Palestinians killed.
In February 2025, the Trump administration followed up with an emergency approval of nearly $3 billion in bombs and demolition kits for Israel. The package included 35,529 general‑purpose bomb bodies for 2,000‑pound bombs and 4,000 bunker‑busting bombs, as well as thousands of 1,000‑pound bombs and Caterpillar bulldozers. The sale bypassed normal congressional review and used emergency authorities; it was the second such emergency action that month. Ari Tolany of the Center for International Policy argued that the administration’s plan to sell Joint Direct Attack Munitions (JDAMs) to Israel risked aiding and abetting war crimes because these weapons “have been used to level Gaza and kill thousands of civilians.”
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.
Trump’s Ukraine 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 to remove barriers and facilitate trade among states and nations. Threatening to impose 100% 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.
America’s founding statesmen repeatedly cautioned against entangling the young republic in the endless quarrels of Europe and the wider world. In his 1796 Farewell Address, President 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.” He acknowledged existing treaties but insisted that it would be “unwise to extend them.”
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” and “the support of the State governments in all their rights, as the most competent administrations for our domestic concerns and the surest bulwarks against antirepublican tendencies.” 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, which a frugal government should avoid.
Supporters of large foreign‐aid packages often point to humanitarian concerns. Russia’s invasion has caused immense suffering in Ukraine, and Hamas’ 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 Tenth Amendment’s promise that undelegated powers are reserved to the states or the people? Jefferson’s warning that a single extra‐constitutional step would lead to a boundless field of power applies with full force.
There are also practical dangers. The Trump administration’s policy of threatening massive tariffs to coerce other countries could ignite trade wars, harming American farmers 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—bombs that can flatten entire city blocks—deepens America’s entanglement in a conflict that many around the world see as genocide. Already, global critics call for an arms embargo on Israel; continuing to supply munitions risks making the United States complicit in alleged war crimes. 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.
More fundamentally, unlimited foreign aid undermines accountability. When the federal government spends billions overseas, the average citizen has little influence over how that money is used. The states and local communities, whose resources are diverted through federal taxation, cannot easily reclaim them. This is precisely the tyranny Madison and Jefferson feared—a remote central government using the Treasury for purposes far beyond its delegated authority.
What might a constitutionally faithful approach to international conflicts look like? First, Congress should recognize that its powers are limited to external objects 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—for example, if foreign aggression directly threatens the United States or its treaty obligations—Congress should follow the proper procedure: debate, vote and, if necessary, declare war. There is no substitute for constitutional deliberation. 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.” Only Congress represents the states and the people and therefore can ensure that war is undertaken only when absolutely necessary.
Third, the United States should return to Washington and Jefferson’s counsel of nonpermanent 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. As Washington put it, America should avoid “interweaving our destiny with that of any part of Europe,” and Jefferson urged “peace, commerce, and honest friendship…entangling alliances with none.”
A constitution of enumerated powers is more than a parchment barrier; it is the guardrail that preserves a free and self‑governing republic. The Trump administration’s decisions to supply huge quantities of arms to Ukraine and to resume shipments of massive bombs to Israel, while perhaps motivated by geopolitical calculation or partisan politics, cannot be justified by any enumerated power. They are precisely the sort of “boundless field of power” Jefferson warned against when he said that powers not delegated are reserved to the states and the people. They also run contrary to the Founders’ repeated warnings to avoid entangling alliances and foreign wars.
Sound economic thinking emphasizes that policies must be judged by their incentives and long-term consequences. 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 tomorrow from using the same rationale to police internal affairs of states, nationalize industries or regulate every aspect of life. 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 “benignant 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.
