America’s major alliances date back decades. Washington has been protecting Europe, Japan, and South Korea for longer than most Americans have been alive.

The original justification for this expensive global role was the Evil Empire, as President Ronald Reagan called the Soviet Union. Aggressive communism had to be contained, and America’s allies were in various degrees of prostration at the end of World War II and the Korean War.

For a brief moment of history the U.S. had to take on a unique and oversize international role. But as the world moved into the 1980s, it was the lethargy and stinginess of America’s allies that prevented them from taking over most, if not full, responsibility for their own security.

Washington should stop allowing Asians and Europeans to continue cowering behind it. That they prefer not to do more is understandable. But that is no reason for America to do it for them.

The traditional argument for turning the Pentagon into an international welfare agency was security. That claim has grown threadbare given how the existential threats that once confronted, or at least plausibly affected, the U.S. have disappeared.

No peer competitor, no contending global power, no countervailing alliance, no cohesive coalition of adversaries, no credible threat to global commerce, no anything at all.

What remains is, well, paltry compared to threats of global and nuclear conflict. Genuine problems, such as terrorism, but ones requiring limited, nuanced responses, not big alliances, aggressive wars, foreign occupations, endless bombing, and more. The Pentagon could do and spend far less while still safeguarding Americans.

So then, what are the existing alliances for?

Anthony V. Rinna of the SinoNK group recently suggested protecting commerce: “Managing the threat posed by instability on the Korean Peninsula to the United States’ economic interest cannot be done only through a combination of diplomacy and nuclear deterrence. It also requires the continual presence of American conventional armed forces.”

Why?

First, the Republic of Korea vastly outranges its antagonist on virtually every measure of power: 40 times the GDP, twice the population, overwhelming international connections. Even if Washington had sufficient economic interests at stake to warrant a defense guarantee in theory, one would not be necessary in practice. Foreign policy should reflect international realities, which change over time.

Second, the age of mercantilism long passed. The military should not be used to promote normal economic interests. Washington would end up squandering the money and lives of all Americans to protect the profits of a few.

While economic survival might become an existential issue, that certainly is not at stake with Asian, let alone South Korean, trade. There’s also an interest in ensuring navigational freedom, including commercial traffic.

But neither of these justifies defending a mid-size ally with modest economic ties to America. At a fraction of today’s cost Washington could threaten retaliation against any strike on international shipping—a far more sensible step than entering someone else’s war.

While the U.S. would suffer more if commerce with China and Japan was disrupted, a renewed Korean war likely would have only limited impact on that. Pyongyang’s reach is modest and the DPRK would have no incentive to encourage other nations to become belligerents against it.

Third, Seoul’s neighbors have far more at stake and should act to limit the damage from any conflict. Indeed, a second Korean war would have a variety of humanitarian, economic, and military impacts on China and Japan.

Turning friendly states into long-term military dependents is bad enough. As I wrote for National Interest, “doing the same for China would be bizarre. Washington has been attempting to convince the PRC that North Korea harms Chinese as well as American interests. The best way to make that argument would be to step back and allow Beijing to confront its North Korean problem directly.”

Whatever past arguments for Washington’s role as global policeman, times have changed. America’s populous and prosperous friends should defend themselves, including their economic interests.