What did the u. s. learn to be unsuccessful war tactics

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 They include more than 2,000 pages of previously unpublished notes of interviews with people who played a direct role in the war, from generals and diplomats to aid workers and Afghan officials.

What does this mean ? ?