President Trump. (Nicholas Kamm/Agence France-Presse via Getty Images)

Before becoming a presidential candidate, Donald Trump called for a “speedy withdrawal” of U.S. forces from Afghanistan. During the campaign, he backed off the “speedy” part of that phrase, but he still touted his opposition to “nation building.” On Monday night, though, Trump became the latest president to prolong what is already the longest war in American history, announcing that more U.S. forces would be deployed there even though “my original instinct was to pull out.” For once, Trump should have stuck with his instincts. The United States has no long-term strategy for winning the war, and there is no voter interest in the troop levels that would be required to win anyway. It’s past time to get out of Afghanistan.

The situation on the ground is dispiriting. Sixteen years in, the Taliban still controls more than a third of the country. The Afghan government and armed forces are shot through with corruption. Despite the United States spending billions on counter-narcotics operations, opium production remains at or near record highs. Thousands of Americans and tens of thousands of Afghans, including more than 30,000 civilians, have died.

After nearly two decades of war, the United States does not appear to have any long-term strategy for ending the conflict. When Gen. John Nicholson, commander of U.S. forces in Afghanistan, testified before Congress in February on U.S. strategy in the country, his 20-page statement did not mention “win” or “victory” once. Instead, he referred to a “‘hold-fight-disrupt’ methodology.” What would bring the troops home? A truly functional Afghan state? A settlement between the Taliban and the Afghan government? The Taliban contained — its recent momentum blunted and perhaps some territory retaken? Or something else?

Trump’s address did not help: “From now on, victory will have a clear definition. Attacking our enemies, obliterating ISIS, crushing al-Qaeda, preventing the Taliban from taking over Afghanistan and stopping mass terror attacks against America before they emerge.” All of the above, in other words, which contra Trump’s claim is not a “clear definition.” How all these goals are to be accomplished is largely left up to the imagination — Trump offered almost no specifics, including the size of the troop increase. Even the slightly detailed policies he did mention have been tried already: He pledged to withhold money from Pakistan over its sheltering of terrorist groups — exactly what the Obama administration did last summer.

Of course, Trump is not the first president caught in the Afghanistan quagmire: George W. Bush’s hope for swift victory never materialized. Barack Obama’s pledge to leave the country before the end of his time in office went unfulfilled. But these struggles should not surprise anyone. History shows that defeating a highly mobile and determined force in inhospitable terrain would require far larger numbers of troops, including hundreds of thousands of Americans, to have a chance of success. There’s little evidence that the Trump administration or American voters are interested in a commitment of that magnitude.

That is not to say that defeating the Taliban is not a worthy objective — but U.S. leaders must be more honest about what it would take to win. And if we as a country are not willing to make that commitment, then we should not be asking so many Americans and Afghans to make the ultimate sacrifice.

Regardless of the outcome in Afghanistan, our experience there should lead to a complete reevaluation of how and when we use military force abroad. The strongest military in history been stuck in a war for the better part of two decades because political leaders continue to indulge the idea that a military built for conventional warfare can be used for unconventional warfare, and that said unconventional warfare can be fought on the cheap. No president or general wants to be the person who admits it’s time to leave Afghanistan. Few politicians or pundits want to step out of line and say that using a $600 billion-a-year military to rebuild countries may not be the best strategy. It has become easier to pretend that war in Afghanistan can be ended. Now that Trump has meekly authorized another increase in troop levels, it seems a given at this point that the longest war in American history will continue for several more years. By the end of the decade, there almost certainly will be men and women serving in Afghanistan and joining the list of nearly 23,000 U.S. casualties who were not even born when al-Qaeda attacked on Sept. 11. Given that shocking milestone, it is time to radically reconsider our strategy. Sadly, the president has caved again and decided otherwise.