Donald Trump’s decision that he would send more troops to Afghanistan – announced Monday night in a prime-time address to the nation – was the right call, but it was a 180-degree turn from what he promised during the campaign.

As both a private citizen and as a presidential candidate, he repeatedly criticized the war in Afghanistan, urging the United States to end the conflict there. Monday night, he largely abandoned that idea, recommitting the U.S. to the nation’s longest-running war.

Trump did dress up this decision with his own rhetoric, promising that American troops would no longer be nation-building but instead killing terrorists. If that actually leads to a change in policy, that would be a good thing: for years nation-building, though successful elsewhere in the world, has seemed to be a pointless exercise in Afghanistan. No matter how many schools and hospitals we build, the nation always seems to be in the grip of anarchy – or just on the verge of it. If the U.S. focuses its efforts in Afghanistan on defeating the Taliban, instead of trying to build a functional democracy, we might have a chance at some kind of success there – though exactly what form that will take remains to be seen.

Trump is taking an enormous risk here, both strategically and politically.

Politically, many of his most ardent supporters will no doubt be disappointed that he ditched his early promises to get out of Afghanistan. Before he became a candidate, he frequently criticized the cost of the war and its lack of success, often employing the type of ‘bring the war dollars’ home language more commonly used by the left. As a candidate, though, he stepped back from that, recognizing that he could not immediately bring the troops home. Now, as president, he’s doing the complete opposite by sending more troops there.

This kind of change is nothing new in American politics. Many a presidential candidate has employed isolationist language while on the hustings, only to have their minds changed completely once they sat behind the Resolute desk. Obama also promised to end the war in Afghanistan during the 2012 campaign, but instead raised troop levels there – while simultaneously ratcheting up the drone program. Before him, George W. Bush campaigned against nation-building and using the U.S. military as an international sheriff, criticizing many of Clinton’s military actions abroad. As President, of course, he launched the wars in Iraq and Afghanistan and engaged in a global war on terror after September 11.

Strategically, Trump will face critics who argue that this change is more rhetorical than anything. After all, it might be all well and good to move away from nation-building, but if you’re simply increasing the troop levels instead is that really much of a change?

It’s a more militaristic approach, to be sure, but it might not necessarily be more successful. Indeed, although Trump promised that the U.S. wouldn’t be leaving Afghanistan before achieving success there, he offered no hints at a definition of that success.

Is success in Afghanistan simply defeating the Taliban? If so, how thorough does that defeat have to be?

It’s unlikely (though not impossible) that the Taliban will ever sign a formal peace treaty with the government in Kabul and lay down their arms. They’re in it for the long haul, with an experienced insurgency that is embedded within the local population and prepared to continue no matter how long it takes. They didn’t abandon their fight after the last surge of troops, and they’re not likely to after this surge, either.

The war in Afghanistan isn’t just a conflict launched by the United States and its allies after the September 11 attacks. It’s also a civil war that, next year, will be entering its 40th year. That’s an enormous part of the reason that it’s so difficult for the U.S. to define success in Afghanistan: it’s not our conflict, just one we were drawn into after an attack.

It’s certainly in the interests of the U.S. to defeat the Taliban. They’re a violent extremist group with international reach that befriends those who wish to destroy us. If we stick to that goal, of defeating the Taliban rather than ending the war or establishing a stable government, we might be able to declare victory and go home. However, there’s every reason to believe that after we leave, chaos, violence and corruption will continue, making it difficult to tell victory from defeat.

Jim Fossel, a conservative activist from Gardiner, worked for Sen. Susan Collins. He can be contacted at:

[email protected]

Twitter: @jimfossel