How Can Europe Reduce Its Military Dependency on the United States?

Even the European members of NATO say that they must do more to defend themselves as the war in Ukraine grinds on and the United States shifts its priorities to Asia and a rising China.

The possibility that former President Donald J. Trump will return to the White House heightens the concern, given his repeated threat to withdraw collective defense from countries that don’t pay their way in the alliance.

In fact, European member states have made considerable progress in the last few years to restore more credibility to deterrence against Russia. But they began from a low base, having cut military spending sharply after the collapse of the Soviet Union and reacting with complacency to Russia’s annexation of Crimea in 2014.

There is a lot more that the Europeans should do to become less dependent on the United States, NATO officials and analysts said this week during the alliance summit in Washington. That includes committing more money to defense, building up arms manufacturing and coordinating the purchase of weapons systems that could replace those now provided solely by the Americans.

With President Vladimir V. Putin of Russia busy with Ukraine and his military degraded by the fierce fighting there, European and NATO officials believe there is a window of perhaps three to seven years before Mr. Putin might be tempted to test the NATO alliance. But will Europe use that window to rearm?

Here are four of the key gaps that the Europeans should fill if they are serious about reducing their dependency on the United States for their own defense.