After President Trump gave Secretary of Defense Jim Mattis the authority to set troop levels in Afghanistan, the Pentagon announced it will send an additional 4,000 troops to the embattled nation. Mattis, who has acknowledged that the United States is “not winning in Afghanistan right now,” is believed to favor a more aggressive strategy that would require thousands more troops beyond the 9,800 already deployed.

The goal, Mattis told Congress, is to reduce the threat to the Afghan government to a non-existential level.

The fact that the United States has made so little progress toward this goal in the 16 years American troops have been in Afghanistan is bad enough. The fact that the general strategy under consideration — surge more American forces — has yet to achieve any enduring gains since 2001 is even worse.

But worst of all is the fact that the Trump administration, led by a commander in chief who campaigned for President by expressing consistent skepticism about overseas engagements, hasn’t offered a single serious argument for the continued U.S. mission in Afghanistan.

The main argument advocates make for sticking it out in Afghanistan — preventing terrorism against the U.S. — no longer holds water. After disrupting Al Qaeda’s operations and dispersing its members in the wake of 9/11, Afghanistan itself represented little threat of terrorism.

This is not to say that there are no terrorists there. But terror groups that pose a threat to America currently operate in Iraq, Nigeria, Somalia and Pakistan at a much higher rate than in Afghanistan. If the threat to America drives where U.S. forces are sent, then surge forces should be sent into those four other countries first.

Another unpersuasive argument is that the U.S. must keep troops in Afghanistan to prevent the Taliban from ending the country’s experiment with democracy. The truth is that even if the U.S. is willing to make unprecedented efforts, it will have little control in the long run over political outcomes in Afghanistan.

Freedom House assessed Afghanistan as “Not Free” this year, the same rating it gave Afghanistan in 2001 when the Taliban was in control. For the brief period of 2006 to 2008, the country was assessed as “Partly Free,” a time that predates the U.S. surge that began in 2009.

Eventually, the U.S. will leave. The Taliban will not. A continued U.S. military presence in the near term may give it some leverage over any potential peace talks between the Afghan government and the Taliban. But to date, that leverage has bought little or no progress and has merely extended the ongoing conflict, which killed 3,500 Afghan civilians in 2016 alone. Meanwhile, the Taliban control more territory than at any point since 2001.

More to the point, American security does not depend on who runs Afghanistan. The U.S. learned this lesson in Vietnam, a conflict both Mattis and National Security Adviser H.R. McMaster have studied extensively. Despite monumental efforts, the U.S. could not prevent South Vietnam from falling to the Communist North. Even though the loss was a psychological blow, the Communist dominoes did not continue to fall, and America’s fundamental security remained strong.

Although no one wants to see the Taliban back in control, the hard reality is that preventing that future is not worth the costs the U.S. has already paid, much less the additional costs that will accrue from another surge.

The honest reason for America’s enduring military commitment is that no President wants to be the one who “lost Afghanistan.” Though pundits and partisans criticized both George W. Bush and Barack Obama for their records in Afghanistan, each of them maintained just enough of a military and rhetorical commitment to avoid getting blamed for losing the war.

Trump thus inherits a war and nation-building project that he had long criticized, but which he must now continue or find an honorable way to end if he wants to avoid getting tagged with the loser label. That conundrum may help explain why he recently gave Mattis the authority to handle the Afghanistan strategy from the Pentagon. That way, when progress fails to materialize or things go south, Trump will have someone to blame.