The recent breakdown in Afghan peace talks is disappointing. Coming so close to the anniversary of the Sept. 11, 2001, terror attacks makes it more so.

On today’s date, 18 years ago, 19 Muslim hijackers took control of four jetliners. Two were flown into the World Trade Center in New York City and one into the Pentagon, and one that was believed to be headed for the White House crashed in Pennsylvania as passengers attempted to storm the cockpit.

Approximately 3,000 people were killed.

The mastermind of the attack was Osama bin Laden, a Saudi Arabian who was angered by the presence of American troops in his native country during the first Iraq war. bin Laden formed an organization called Al Qaeda, which was linked to a number of terrorist attacks before 9/11.

The United States had been hunting bin Laden for years, but he apparently was not a high priority. As the nation reeled from the aircraft attacks, he became one.

bin Laden was believed to be in hiding in Afghanistan. The United States asked the government of Afghanistan — a group called the Taliban — to turn him over. They refused. The U.S. attacked Afghanistan in late 2001.

The Afghan war was part of what President George W. Bush called “the War on Terror.” Another part of it was the war in Iraq that started in March 2003, which drew intelligence and military assets out of Afghanistan even though bin Laden had not been captured. Some sources speculated bin Laden would have been captured much earlier had the U.S. remained focused on him.

In any event, bin Laden was located in neighboring Pakistan in 2011 and killed during an attack by American SEALs.

But American troops have never left Afghanistan.

The original motive — to capture bin Laden — transformed into the ouster of the Taliban, then the creation of a democratic government in Afghanistan. The Taliban is no longer in power, but it still holds sway over about half the country, according to Associated Press coverage. The government in Kabul is viewed as a puppet of the United States and is severely weakened by allegations of fraud and corruption as well as continued terror attacks linked to the Taliban.

The number of U.S. troops in Afghanistan has varied over the years but now stands between 13,000 and 14,000, the AP reported. When Donald Trump campaigned for president in 2016, one of his goals was to bring all of those troops home.

An agreement announced last week looked as if it would help make that a reality. It called for a reduction of 5,000 troops within 135 days of the signing of the agreement. In return, the Taliban promised a reduction in violence and agreed to meet with Afghans both in the current government and outside of it to negotiate a lasting peace.

The agreement faced myriad challenges.

The Taliban would not negotiate with the current government, declaring it a U.S. puppet. Some top American officials believed the Taliban could not be trusted to keep an agreement. The current Afghan government insisted on holding presidential elections Sept. 28, perhaps in hopes of adding to its legitimacy, but negotiators urged that it be delayed because all the Afghan political class would be focused on the election rather than any peace talks. The Taliban continued its attacks, including one that killed an American serviceman days after the agreement was announced.

On Saturday, President Trump announced that he’d planned a secret meeting with all the sides at Camp David to finalize the agreement, but that the meeting had been canceled after the attack that killed the serviceman. On Monday, he said the peace talks were “dead.”

If that is truly the case, where does that leave us? Presidents of both parties have sought to pull our troops from that war-torn land, but they feared the vacuum we’d leave behind. An agreement involving the Taliban, the Afghan government and the United States offered the best chance for us to leave without setting up a civil war or a terrorist paradise.

Now it seems likely we’ll have troops in harm’s way there for many years to come.