Words have consequences. Trump’s domestic political base may think it’s just fine to take the president seriously but not literally. Treaty allies like France can’t be so cavalier. If Macron is now exploring France’s options by talking up the prospect of a European army while talking down the threat from Russia, it’s because that’s where Trump’s wild rhetoric and behavior have led him.

But then we get to the other side of the ledger.

In 2011, Secretary of Defense Robert Gates warned of a “dim if not dismal future” for the alliance if states such as Germany continued to underspend on defense. Nearly eight years later, a German parliamentary report found that fewer than half of the country’s fighter jets, and not one of its six submarines, were combat worthy. The German defense minister recently announced that she does plan to meet NATO targets on military spending, but not until 2031.

To American policymakers of any administration, that sounds like something between a bald insult and a bad joke.

Most other NATO members are no better. Canada, for instance, spends just 1.27 percent of its gross domestic product on defense (the NATO target is 2 percent) and cannot meet its obligations to defend North America’s airspace. When Justin Trudeau was overheard at the summit belittling Trump for taking too long with his press conference, the Canadian prime minister sounded to many Americans like a child whining that a working parent had kept him waiting for supper.

All of this means that when Macron and other European leaders muse about creating an autonomous European defense force, they are, as one seasoned Parisian observer put it to me, “playing with cards they don’t have.” Even sizable increases in defense spending wouldn’t fill the gap that an American departure from Europe would leave: Roughly half of European defense spending goes to salaries and pensions, not warfighting capacity.