But it’s not clear the U.S. can preserve these gains even if it does send another few thousand troops. (Remember that a percentage of every dollar America spends on the Afghan military winds up in Taliban hands and that Russia, Iran, and Pakistan can match America’s escalation with an escalation of their own.) At best, maintaining these gains requires war as far as the eye can see. The Afghan government will never have the resources to fight the Taliban on its own. Donor aid constitutes two-thirds of its annual budget. Yet Trump officials themselves reportedly reject the idea that American troops will remain in Afghanistan indefinitely.

Escalation doesn’t only mean more dead, injured, and psychologically scarred Americans. It also means a substantial financial expense. According to the Watson Institute at Brown University, the Afghan war has already cost the United States more than three-quarters of a trillion dollars. And it will cost an additional $40-$50 billion more in fiscal year 2017. That’s five or six times as much as the House of Representatives just added to pay for health insurance for Americans with pre-existing conditions.

And in perhaps the cruelest irony of all, it’s not just American failure that would erode the gains Afghan women have made. American success would erode them too. The U.S., after all, is not trying to vanquish the Taliban. It’s trying to convince them to lay down their arms and join the Afghan government. And if the Taliban agrees, Afghanistan’s government will grow less liberal and less supportive of women’s rights.

It’s hard to imagine that Trump cares. His presidential campaign was nakedly hostile to the notion that the U.S. should expend resources improving the welfare of people beyond America’s shores. If he approves another surge, he’ll likely rely on a second argument: that sending more troops to Afghanistan is necessary to keep Americans safe.

But is it? On the surface, the claim seems plausible. After all, the last time the Taliban ran Afghanistan, al-Qaeda used their hospitality to plot the 9/11 attacks. In theory, al-Qaeda—or ISIS, which boasts perhaps one thousand fighters in Afghanistan—could exploit such hospitality again.

The problem with this argument is that a lot has changed since September 10, 2001, when America’s leaders treated the jihadist terrorist threat as a relative afterthought. The United States now devotes vast resources to preventing terrorists from entering, and across the greater Middle East, it regularly strikes terrorists from the air. In ungoverned spaces in Iraq, Syria, Libya, Yemen, Somalia, and Pakistan, al-Qaeda and ISIS fighters congregate. (They do so in Afghanistan already.) Yet they have failed to carry out large-scale plots inside the United States. As the think tank New America reported in a study last year, “the United States today is a hard target for foreign terrorist organizations, which have not directed and carried out a successful deadly attack in the country since 9/11. This is the result of a layered set of defenses including tips from local communities, members of the public, and the widespread use of informants.” Jihadist terrorists have killed fewer than one hundred Americans on U.S. soil since 9/11. And none of those terrorists received training overseas. As al-Qaeda expert Peter Bergen notes, “Every lethal terrorist attack in the United States in the past decade and a half has been carried out by American citizens or legal permanent residents, operating either as lone wolves or in pairs, who have no formal connections or training from terrorist organizations such as al Qaeda or ISIS.”