The war in Afghanistan is nearly 16 years old. It is the longest in our nation’s history. Many Americans wonder why our soldiers are still there. This widespread frustration is shared by our commander in chief. The Trump administration has not yet announced its plans for Afghanistan in large part due to the president’s reluctance to take action. If he sends more troops into the country, then it becomes his war, and he is not eager to inherit a costly, seemingly intractable conflict. But as President Trump weighs his options he should remember one maxim above all others: The enemy gets a vote. And in Afghanistan, our enemies are on the rise.

The Afghan government is in serious trouble. The Taliban-led insurgency contests or directly controls approximately 40 percent of the country. No area is truly out of its reach. Kabul, the capital, is regularly hit by the Taliban.

There are many in Washington who think this is merely a local concern, without any ramifications for American security. Their opinion is reinforced by a cottage industry of experts, inside and out of government, who act as de facto apologists for the Taliban. President Trump’s top advisers should sweep away this rubbish, which was crafted to serve the Obama administration’s desire to downplay the survival of al Qaeda.

It is essential to remember that the Taliban is al Qaeda’s key ally and that the two are inseparable. In the wake of the 9/11 hijackings, President George W. Bush demanded that Taliban leader Mullah Omar turn over Osama bin Laden, who had sworn an oath of allegiance (a bayat) to Omar. The Taliban chieftain refused; Omar chose to lose his country rather than betray his honored guest. Al Qaeda celebrates his obstinance to this day.

Bin Laden was killed in May 2011, and Omar died sometime in 2013. Bin Laden’s successor, Ayman al Zawahiri, swore allegiance to Mullah Mansour, Omar’s replacement. After Mansour was struck down by an American drone strike in Pakistan in May 2016, Zawahiri quickly rehearsed the same oath to Mullah Haibatullah Akhundzada.

There are numerous ties between al Qaeda and the Taliban. Akhundzada’s top deputy is Sirajuddin Haqqani, who oversees the Taliban’s military operations. Files recovered during the May 2011 raid on bin Laden’s compound reveal that al Qaeda’s men have fought alongside Haqqani’s forces for years. And Haqqani’s father, Jalaluddin, was one of Osama bin Laden’s earliest and most influential backers.

In September 2014, Zawahiri publicly announced the creation of Al Qaeda in the Indian Subcontinent (AQIS). Its primary goal is to restore Taliban rule in Afghanistan, and AQIS’s men fight under the Taliban’s banner.

In October 2015, U.S. and Afghan forces raided two massive al Qaeda training camps in southern Afghanistan. One of the camps, approximately 30 square-miles in size, may be the largest al Qaeda training camp in its history. Both camps were supported by the Taliban.

Despite the Taliban’s obvious partnership with al Qaeda, the Obama administration pursued feckless negotiations with its leadership. The Taliban used these talks to extract a series of concessions, including a political office in Qatar that is useful for fundraising, the removal of several key Taliban figures from the U.N.’s terrorist sanctions list, and the release of five top Taliban commanders from Guantánamo. The United States secured, in return, the release of Sgt. Bowe Bergdahl, an accused deserter. That’s it. The Taliban neither forswore al Qaeda nor agreed to any type of ceasefire. And they never will.

As President Trump considers his options in Afghanistan, he should remember that crucial truth. There are many reasons the United States today has so little to show for the many sacrifices made in Afghanistan over the past 16 years: from an unwillingness to confront Pakistan and inadequate resourcing to two terms of strategic drift caused by an uncertain commander in chief. But among the most important reasons we’ve struggled is an eagerness to see the Taliban as the potential partner we wish it would be rather than the determined enemy it is. If Trump’s policy continues this dangerous self-delusion, it will fail.

If the Taliban is able to resurrect its Islamic emirate in Afghanistan, it will be a momentous victory for al Qaeda’s cause. Jihadists around the globe have sworn their allegiance to Zawahiri and, through him, to the Taliban’s leader. They are trying to build their own caliphate, similar to the one established by the Islamic State, with Kabul as its capital. If they succeed, it will have dire ramifications for international security.