One month later, the scenario Mr. Biden deemed impossible has become a horrifying reality. In recent days, the world has watched panicked civilians cling to U.S. military aircraft in a desperate attempt to escape the chaos unleashed by Mr. Biden’s reckless retreat. American diplomats had to beg our enemies not to storm our embassy in Kabul. Taliban fighters have seized scores of American military vehicles, rifles, artillery, aircraft, helicopters and drones.

The Biden administration’s disastrous withdrawal from Afghanistan is a foreign-policy humiliation unlike anything our country has endured since the Iran hostage crisis.

It has embarrassed America on the world stage, caused allies to doubt our dependability, and emboldened enemies to test our resolve. Worst of all, it has dishonored the memory of the heroic Americans who helped bring terrorists to justice after 9/11, and all who served in Afghanistan over the past 20 years.

In February 2020, the Trump administration reached an agreement that required the Taliban to end all attacks on U.S. military personnel, to refuse terrorists safe harbor, and to negotiate with Afghan leaders on creating a new government. As long as these conditions were met, the U.S. would conduct a gradual and orderly withdrawal of military forces.