President Biden often says that the contest between democracy and authoritarianism is the defining challenge of our time.

He’s right.

Yet Biden has a funny way of showing it.

Under Biden’s watch, the number of global democracies has decreased by one. Two others are under threat of invasion and extinction.

What happened in Afghanistan, and what might happen in Ukraine and Taiwan, is a reminder that democracies do not vanish because of a failure to pass a partisan agenda or win an election. They die when the rule of law collapses.

And that can happen in two ways. A polity can descend into anarchy. Or an adversarial force can replace a democratic state’s monopoly of violence with its own.

Both threats are serious. But domestic challenges should not blind us to external dangers. For the last 80 years, American power has sustained and expanded the ranks of democratic nations.

The tinier and more fragile the state, the more hazardous its neighborhood, the more it depends on American guarantees, American aid, and American might. Remove America from the equation, and the jackals take its place.

That is what happened when America cut off aid to South Vietnam in 1975. It is what happened last summer when President Biden overruled his national security team and the generals on the ground and withdrew U.S. forces from Afghanistan with no plan for the evacuation of U.S. citizens and legal permanent residents as the Taliban advanced.

The man who condemned Afghanistan to misery now says that the contest between authoritarianism and liberal democracy will define the twenty-first century. What he says is right. But what he does is wrong. Terribly wrong.

Consider Ukraine. For the second time this year, Russian dictator Vladimir Putin has built up his forces across Ukraine’s eastern border. A Russian invasion is a real, if unlikely, possibility.

President Biden is admirably vocal in defense of Ukraine’s independence. But he is also playing into Putin’s strategy of “reflexive control.”

Biden warns of sanctions, an end to pipeline construction, and reinforcement of NATO allies in Eastern Europe. The trouble is that the measures would be punitive. They’d happen only if Putin invades.

This is like telling your kid to behave or else you will send him to his room. Chances are he won’t listen. Why? Because he’s heard the same thing many times before without lasting consequences.

At this point, Biden has done nothing concrete, has established no facts on the ground, to suggest to Putin that an invasion of Ukraine would be contrary to Putin’s interests.

Deterrence doesn’t run on promissory notes. Deterrence raises the cost of hostile action in the here and now. Deterrence is about keeping Putin on his toes: by calling for increases in the defense budget, by reinforcing the Baltic states now rather than later, by selling drones and other materiel to Ukraine, by pledging construction of additional Liquid Natural Gas (LNG) facilities in Poland, Ukraine, and Latvia.

What’s happening in Ukraine today is the result of what happened in Afghanistan over the summer. And what might happen in Taiwan in the coming years depends on what happens in Ukraine now.

The failure of American nerve in Afghanistan caught the attention of authoritarians everywhere. They watched as America bolted and a democracy collapsed. They saw that democracies don’t live or die on talk. Democracies live or die upon their willingness to use force to defend their way of life.

And that willingness, in turn, depends on the leadership and support of the world’s oldest, richest, and most powerful constitutional democracy.

This isn’t theory. Ask the Afghans. Democracies perish when America bugs out.