America’s major alliances date back six to seven 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 short moment of history the U.S. had to take on a unique and oversized international role to preserve the “free world.”

But that moment passed long ago—actually, even before the end of the Cold War. By the 1960s most of Washington’s Asian and European allies had recovered economically. With serious effort—which one would expect from nations facing serious, even existential security threats—they were capable of at least matching their potential antagonists. As the world moved into the 1980s it was evident that only their own lethargy and stinginess prevented America’s friends from taking over most, if not full, responsibility for their own security.

Today it is frankly unbelievable that Washington allows its Asian and European allies 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: we live in a dangerous world, etc., etc. That argument has grown threadbare given how the existential threats that once confronted, or at least plausibly affected, the United States have disappeared. No peer competitor, no ideological contest, no contending global power, no countervailing alliance, no cohesive coalition of adversaries, no credible threat to global commerce, no nothing.

What remains is—well—paltry compared to threats of global and nuclear conflict. Lots of tragedy, irritating inconvenience, abundant frustration, occasional threats to individuals, limited terrorist attacks. Genuine problems, but ones requiring limited, nuanced responses, not big alliances, carrier groups, aggressive wars, foreign occupations and endless bombing. Washington’s strategy and force structure remain mismatched to the security threats facing America. 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 suggests protecting commerce. In a recent TNI article, he argues,

“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: forty times the GDP, twice the population, overwhelming international connections. Indeed, the North’s allies of the Korean War (China and Russia) would not support Pyongyang in a renewed conflict. So even if Washington had sufficient economic interests at stake to warrant a defense guarantee in theory, one would not be necessary in practice. Seoul has a stronger incentive to provide for its own defense. And it is capable of doing so.

Foreign policy should reflect international realities, which change over time. The ROK was vulnerable to renewed North Korean aggression at the conclusion of the Korean War in 1953. Today Seoul can do whatever is necessary to deter and defeat the Democratic People’s Republic of Korea. There’s no need for America to defend that which could be defended otherwise.

Second, the age of mercantilism is long gone. The military should not be used to promote economic interests. 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, as well as keeping hostile forces away from the United States. 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—as it did during the Iran-Iraq War, a far more sensible step than actually entering someone else’s war.

Spending billions to defend a trading partner just for its business connections would be a very bad investment. Washington would end up squandering the money of all Americans to protect the profits of select Americans. Moreover, the price if the conventional tripwire is triggered would be paid in blood as well as cash. If the North develops deliverable nuclear weapons, the cost could turn out to be astronomical.

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. A conflict would be most likely to inflate shipping costs, not end trade, like the Gulf tanker war of three decades ago.

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. Any effect on commerce would reach well beyond that with America. The best way to constrain the DPRK would be to encourage Beijing to take a more active role, which it likely would do if it knew that it would bear the full consequences of North Korean aggression.

Turning friendly states into long-term military dependents is bad enough. Doing the same for China is 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. The United States certainly should not go to war to protect commercial markets and trading partners. Rather, America’s populous and prosperous friends should defend themselves, including their economic interests.