It is becoming harder, though, for America to maintain this global posture. Eventually, it may become impossible, in part because we helped create the conditions that allowed other countries to prosper and grow. There may come a time, not too far in the future, when Americans would be surprised to hear that they are responsible for keeping peace on the Korean Peninsula.
Americans should be debating how to manage that transition in a way that avoids destabilizing the rest of the world. Unfortunately, if the current administration’s maneuvers between the two Koreas are any indication, this is the last thing on the minds of policymakers.
There is no question that America’s share of global wealth is shrinking. By some estimates, the United States accounted for roughly 50 percent of global output at the end of World War II. By 1985, its share stood at 22.5 percent. It has fallen to 15.1 percent today, and the International Monetary Fund projects that it will slip to 13.7 percent by 2023.
The proliferation of various technologies — from crude explosives to advanced robotics — has made it easier for even relatively small and weak countries and nonstate actors to challenge the big and powerful United States. These days any truly determined country, even a very poor one like North Korea, can develop nuclear weapons to deter attacks.
Yet Americans may be the last people to recognize the changing shape of global power. It’s not that senior national security officials don’t understand that they have a problem. The Trump administration’s National Defense Strategy, for example, speaks of “an ever more lethal and disruptive battlefield” and worrisome “trends” that “will challenge our ability to deter aggression.”
Its answer? Try harder.
The document predicts that America’s allies will lose faith and the country’s global influence will wane unless taxpayers commit to “devoting additional resources in a sustained effort to solidify our competitive advantage.”
The problem is, the United States already spends more on its military than the next seven or eight nations combined. Total annual expenditures, including for the wars in Iraq and Afghanistan, have averaged $561 billion since 2001. So, how much more must Americans spend to maintain a military edge sufficient to deter attacks against others?
About $196 billion more, on average, over the next five years. The Trump administration projects spending $3.78 trillion from 2019 to 2023, or $756.9 billion a year. Some doubt that even that will be enough.
Ideally, this additional spending will discourage others from challenging us. Even if it did, however, that would require Americans to accept less domestic spending, higher taxes or both in order to allow others to underspend on their militaries.
But what worked before might not work in the future. America’s insistence upon maintaining primacy at all costs may stimulate greater resistance from the likes of China and Russia. And the risk that the United States gets drawn into wars that it need not fight and cannot win will remain high, no matter how much we spend. We are faced with the prospect, then, of frequent uses of force — like the missile strike against suspected Syrian chemical weapons sites this month that even supporters admitted was unlikely, by itself, to accomplish much.
There are, however, alternatives to simply spending more and trying harder. Of course, the easy, and unpalatable, options would hand over the reins of global leadership to China, or simply have American forces withdraw quickly and let the chips fall where they may.
Instead, America should seek a new arrangement that asks the beneficiaries of today’s relatively peaceful and prosperous world order to make a meaningful contribution to maintaining it. The American security umbrella will stay aloft — and American military power will remain formidable — but others will need to do more.
Rather than treating allies like reckless teenagers who can’t be trusted without Uncle Sam’s constant supervision, or feckless weaklings that will jump at the chance to capitulate to rapacious neighbors, Washington should empower mature, like‐minded states to deal with local challenges before they become regional or global crises.
Some countries, in fact, are already moving in this direction. South Korea has undertaken its own bilateral negotiations with North Korea. Unsettled by Donald Trump’s threats to renege on American security commitments, or offended by his attempt to extract tribute in exchange for American protection, these countries’ leaders are thinking seriously about different security arrangements. As Constanze Stelzenmüller explained in a recent paper for the Brookings Institution, Europeans, in particular, have an “existential” interest in “preserving an international order that safeguards peace and globalization.”
Of course, one purported advantage of an American‐funded global security order is that it supposedly allows Washington to call the shots — and, naturally, some worry that its allies would show less deference and be less willing to comply with Washington’s dictates if they were less dependent upon American power. But that already happens: In fact, some allies have been known to act recklessly when they believe that America has their back. Look at the ruinous war that Saudi Arabia is waging in Yemen, one of the world’s poorest countries. Greater independence could induce greater caution.
And the benefits flow both ways. If Washington was slightly less confident that it could call the tune and expect others to dance, that might help America to avoid costly mistakes. Would the United States have invaded Iraq if it didn’t believe that other countries would help clean up after?
Transitioning to a world with many capable actors won’t be easy. It will require a deft hand to unwind defense arrangements, and patience as others find their way. Given their own domestic spending priorities and continued uncertainty about whether the United States will recommit to the old model, most American allies are likely to take a wait‐and‐see attitude. A gentle nudge might be needed to move them from comfortable adolescence to empowered adulthood.
The columnist Charles Krauthammer once cast decline as a choice, as though, by mere force of will, the United States could remain atop the international order forever.
On the other hand, it was Mr. Krauthammer who in 1990 spoke of America’s unipolar “moment” — a temporary state of affairs, occasioned by a unique set of circumstances that defined the first few years of the post‐Cold War world. That world no longer exists. Wishing it back into existence won’t make it so.The United States is the most important country in the world and will remain so for many years by virtue of its strong economy and prodigious military capabilities. But admitting that the United States is incapable of effectively adjudicating every territorial dispute or of thwarting every security threat in every part of the world is hardly tantamount to surrender. It is, rather, a wise admission of the limits of American power and an acknowledgment of the need to share the burdens, and the responsibilities, of dealing with a complex world. It is about seizing the opportunity to make changes that benefit us and others.
The alternative is a renewed commitment to discourage self‐reliance among allies. That will be an undertaking far more onerous than any the United States has attempted since World War II — and one that is unlikely to work.