By the end of the year, America will complete its combat mission in Iraq, and the Iraqis will take care of their own defense. That’s the gist of President Biden’s announcement Monday as he hosted Prime Minister al-Kadhimi at the White House. If the decision is capability based, and the Iraqis turn out to be ready, then great. America need not take on, nor has it ever sought, battles that others can fight for themselves.

We don’t mind saying, though, that we find Mr. Biden’s approach unconvincing. It may be, as NBC suggests, suggests that the announcement is but an effort at “misdirection” and that little will change. Yet we nurse a concern that Mr. Biden’s latest will prove a prelude to withdrawal from Iraq of the last American forces. That is all too likely to prove to be as catastrophic as Mr. Biden’s surrender in Afghanistan.

In the two months since Mr. Biden’s decision to quit Afghanistan while it is still under attack, the Taliban has quickly racked up victories. It has seized control of a third of Afghan districts and several border crossings. Along the way, Taliban killers have slaughtered those who stuck out their necks to fight with us — most recently an Afghan former U.S. Army translator, whom the Taliban seized at a checkpoint. It beheaded him.

The Taliban now holds more than 70% of Afghanistan’s territory and is moving toward the capital at Kabul. Our intelligence is now estimating that the Afghan government will fall within six months of our departure. Twenty years, $2 trillion, 50,000 lives, including some 2,000 Americans, gone. The situation has grown so perilous that our forces have already stepped up bombings against the Taliban, only now we have to fly in from further away.

If that two-step sounds familiar, recall President Obama’s retreat from Iraq. In October 2008, President Obama withdrew GIs. Isis moved in to fill the vacuum. By June 2014, it had seized several Iraqi cities and was on the outskirts of Baghdad. American GIs were right back, fighting in Iraq. The retreat from Afghanistan reminds of the old saw about how the definition of insanity is doing the same thing twice and expecting a different outcome.

What is it with our national obsession with withdrawals? Our more established — and successful — strategy is that following a conflict, we stay, sometimes for generations. Our GIs are still stationed in Germany, Italy, Japan, and Free Korea, with no plans to leave. Were we to decamp, we wouldn’t bet two cents that peace would prosper on that blood-soaked continent. It doesn’t mean our GIs failed. It means they’re needed abroad.

In respect of nowhere is this more true than Communist China. It seeks to prevent American forces from getting close enough to China to strike. Hence, say, the islands it’s building in the South China Sea. Our strategy seeks the ability to break through China’s theater defenses and protect, Free China, South Korea, Japan, the Philippines, Vietnam, and Indonesia, and ensure freedom of navigation and trade. From where are we supposed to do all this?

Having said all this, we’re not indifferent to the libertarian arguments about war. We’ve parsed Washington’s “Farewell Address.” We seek no entanglements with Europe, or anyone else. The wars we fought in the 20th Century and those we’re fighting in the 21st were launchd upon us — without cause — by foreign enemies using weapons unimagined in Washington’s day. We don’t see how America’s cause is advanced by withdrawing our GIs before the wars are over.