When Donald Trump, the Republican presidential candidate, criticized NATO in a number of interviews earlier this year, he was challenging the foundations of the United States’ military strategy. His attack on Washington’s conventional wisdom has unsettled the U.S. security establishment no less than it has the foreign governments that depend on it, and has drawn criticism from across the political spectrum.

Trump, however, is right. U.S. policy toward its allies really is “obsolete,” as Trump termed NATO. The United States remains remarkably secure and faces no serious—let alone existential—threat akin to that formerly posed by the Soviet Union, the enemy that most U.S. alliances were formed to oppose. Moreover, Washington’s Asian and European allies are prosperous and industrialized states that are more than capable of protecting themselves.

Unfortunately, U.S. strategy currently appears to endorse the idea that whatever is, must forever be. But the fact that Washington has defended countries for decades does not mean that it should continue doing so indefinitely, whatever the costs. Alliances should be a means to an end rather than an end in themselves, and in this case, that end should be to increase U.S. security.

BEARING THE BURDEN

Critics of Trump have been quick to invoke the danger of reducing U.S. strategic commitments in the face of a newly assertive Moscow. For instance, Anthony Cordesman, a strategic analyst at CSIS, has warned against “giving up Europe to Russia.” No one wants this outcome. But the point is that Moscow cannot have Europe unless the European Union, which possesses a greater population and GDP than the United States (not to mention Russia), allows it to do so. The Europeans are fully capable of defending their own interests without U.S. help, and the ancillary benefits to Washington of military cooperation, such as base access, do not require the extension of security guarantees.

The Europeans are fully capable of defending their own interests without U.S. help, and the ancillary benefits to Washington of military cooperation, such as base access, do not require the extension of security guarantees.

In his comments, Trump has mostly targeted the high cost of the United States’ overseas commitments, complaining that the country’s allies have broken their promises to spend more on their militaries and joint exercises. As he explained to The New York Times in March, “NATO is unfair to us, to the United States. Because it really helps [our allies] more so than the United States, and we pay a disproportionate share.” Thus, he suggested charging nations dependent on the United States for their security.

More is at stake than an unfair financial burden, however. In addition to funds, Washington provides a disproportionate share of NATO’s combat capability, with U.S. defense spending accounting for 73 percent of the defense expenditure of the alliance as a whole. Even when the Europeans contribute combat troops to a NATO mission, as in Afghanistan, they use caveats to restrict when those forces can fight. As former Pentagon official Jeffrey P. Bialos, a NATO booster, admitted in The National Interest: “Even with significant budget increases…Europe’s [military] capability gaps will take years to address.”

NATO officials recognize that members routinely violate their commitments to increase outlays on defense. Secretary General Jens Stoltenberg was pleased, therefore, when he proclaimed in January that the alliance was moving in the “right direction.”

Yet the movement was barely noticeable. Last year, outlays by NATO’s European members dropped slightly, by 0.3 percent. This year, there has been a tiny uptick. No one expects sustained, substantial increases. But the Obama administration is proposing to more than quadruple U.S. military spending in Europe to $3.4 billion next year as part of the “European Reassurance Initiative,” along with the deployment of an armored brigade.

A MILITARY PONZI SCHEME

Despite evidence that the United States is overpaying, Trump’s critics claim that strategic commitments are cheap, since allies help pay U.S. deployment costs, which total about $10 billion annually. Such foreign “host nation support” covers roughly half of that expense. For instance, Japan sets the gold standard by paying $1.7 billion annually, according to Brad Glosserman of the Pacific Forum CSIS. Other major allies, such as South Korea and Germany, contribute less than one billion dollars per year.

The idea that defending other nations actually saves Washington money sounds like a military Ponzi scheme—the more countries protected, the more money saved. Defend enough allies, and the United States won’t have to pay anything for its defense. But obviously that’s impossible. If Washington creates a military unit, no doubt it is cheaper if a foreign government helps pay basing costs. However, this avoids the question of whether a given unit should be created in the first place. There is no predetermined correct size and structure for the armed forces. In effect, the defense budget reflects the nation’s foreign policy.

The idea that defending other nations actually saves Washington money sounds like a military Ponzi scheme—the more countries protected, the more money saved.

Every overseas commitment requires additional forces. If Washington decides to defend another nation, it needs more personnel and weapons to do so. If the Pentagon wants to fight two wars rather than one, the Department of Defense requires a larger force structure. If the U.S. government wants to mount humanitarian operations, promote democracy, rebuild failed societies, and engage in other forms of overseas social engineering, it must create and maintain enough units to accomplish those ends. More also must be spent on administration, intelligence, maintenance, and operational costs. There is an additional expense when allied nations are discouraged from contributing more to their own defense.

The price of any particular commitment is difficult to determine. Still, it should be obvious that defending much of Europe, East Asia, and the Middle East requires a substantially larger military than would otherwise be the case. My Cato Institute colleague, Benjamin R. Friedman, projects that Washington could save up to $150 billion a year by adopting a less activist stance. As he explains, the United States’ desire for primacy “requires a large U.S. military, with units permanently deployed in Europe, East Asia, and the Middle East, and with the capability to quickly strike anywhere with air, naval, and ground forces. It sees threats everywhere and prescribes U.S. forces everywhere.” Doing less—focusing on the genuine defense of the United States—would significantly reduce the forces required.

INTERNATIONAL WELFARE

As he so frequently does, Trump got the policy details wrong when he criticized Washington’s stance toward its allies. But he raised important issues long ignored by his most vociferous critics.

The United States’ alliances are expensive. Defending prosperous, populous, industrialized nations around the world transfers wealth from U.S. taxpayers to their counterparts overseas. In effect, the Pentagon has become the federal government’s largest source of foreign aid, turning security assistance into a form of international welfare.

In July, U.S. President Barack Obama announced that “in good times and in bad, Europe can count on the United States—always.” Fine sentiments, but such a commitment doesn’t require relieving the continent of the requirement to defend itself. Indeed, both Europe and the United States would be more secure if the Europeans did more to protect themselves.

After all, Stoltenberg himself complained that “the answer to a more dangerous world is not less NATO, it’s more NATO.” If so, the Europeans should organize and finance more NATO. But they won’t unless they have no alternative. Disturbed by Trump’s statements, a gaggle of European officials went to the Democratic Convention in Philadelphia seeking reassurance from Hillary Clinton’s campaign, which they received. Vice President Joe Biden and others went out of their way to tell the Europeans not to worry—the United States would always subsidize, protect, and even coddle them if necessary.

That is the wrong message to send. Washington had little choice but to protect allied countries after World War II. But that justification disappeared long ago. Instead of turning the U.S. military into a mercenary force by charging for its services, as proposed by Trump, Washington should drop the commitments no longer necessary for U.S. security. Doing so would not only save the United States money, but make it safer as well.