After all, why would any country want to resist U.S.-led order when it seemed to offer prosperity and security to all? Above all, Americans were sure they would face no peer military competitor, and their country’s immense preponderance of armed might, along with the support of so many others, meant that it could expect swiftly and easily to defeat any adversary foolish enough to risk challenging U.S. primacy. That lesson was hammered home by Desert Storm.

But it hasn’t worked out that way. America has faced no global rivals comparable to the Soviet Union of the Cold War, but in three key parts of the world it has faced serious regional challenges to its vision.

The first is the Middle East, where the primary challenge has come not just from states like Iran, but from non-state actors. They have used terrorism to contest their region’s incorporation into the American-led global order whose politics, ideology, and culture they reject. America’s response, in Iraq and Afghanistan, has been to try to create new states that would bring their peoples into the U.S.-led order. That has failed. Likewise, hopes that the Arab Spring might see the countries affected reconstruct themselves on more pro-U.S. lines have been dashed. Instead the state system in key parts of the region has collapsed. This is not all America’s fault. But it is now quite clear America has few options that can make much difference to what happens there in the long term, unless it is willing to commit ground forces far larger and for far longer than it ever did in Iraq.

The second region in which the post-Cold War vision has been challenged is Eastern Europe. President Vladimir Putin has tried to resist Russia’s incorporation into the U.S.-led order, and push its boundaries back from Russia’s borders by reasserting a Russian sphere of influence in its “near abroad.” His use of armed force and political subversion to do this has naturally revived memories of the Cold War.

Here, too, America has found no effective way to respond. Despite U.S. diplomacy backed by sanctions, Putin continues to pressure Ukraine, deploy missiles on Europe’s borders, and make provocative intrusions into European air and sea space. It would appear that only force counts with Putin, and neither America nor its European allies have the conventional forces to confront Russia’s army on Russia’s own borders. The issues at stake, moreover, are simply not important enough to credibly contemplate escalation to nuclear conflict.

Third there is Asia, where the U.S. faces its greatest challenge from China. It can no longer seriously be questioned that China aims to create a new Chinese-led regional order in Asia. Nor can it be doubted that China has the strategic weight and national resolve to mount and sustain this challenge. China today is far stronger, in the fundamental economic sources of national strength, than the Soviet Union ever was. And its resolve in the region is stronger than America’s, because ultimately what happens in Asia matters more to China than to America. It cannot of course match America in aggregate military power, but it can deny America a swift and easy victory in the Western Pacific and raise the costs of U.S. military action beyond what the stakes might be worth.