A confidential trove of government documents obtained by The Washington Post reveals that senior U.S. officials failed to tell the truth about the war in Afghanistan throughout the 18-year campaign, making rosy pronouncements they knew to be false and hiding unmistakable evidence the war had become unwinnable.

The documents were generated by a federal project examining the root failures of the longest armed conflict in U.S. history. They include more than 2,000 pages of previously unpublished notes of interviews with people who played a direct role in the war, from generals and diplomats to aid workers and Afghan officials…

“We were devoid of a fundamental understanding of Afghanistan — we didn’t know what we were doing,” Douglas Lute, a three-star Army general who served as the White House’s Afghan war czar during the Bush and Obama administrations, told government interviewers in 2015. He added: “What are we trying to do here? We didn’t have the foggiest notion of what we were undertaking.”

“If the American people knew the magnitude of this dysfunction . . . 2,400 lives lost,” Lute added, blaming the deaths of U.S. military personnel on bureaucratic breakdowns among Congress, the Pentagon and the State Department. “Who will say this was in vain?”