The General's Letter

Eisenhower addressing the troops in England, June 6, 1944               U.S. Army

We wouldn't be commemorating D-Day so fervidly if it hadn't been a success, but back in the days leading up to the invasion, no one had the benefit of knowing how or whether it would work. Just in case it didn't, General Eisenhower penned a letter in which he took the blame for its failure: http://mentalfloss.com/article/57144/eisenhower-wrote-letter-accepting-blame-d-days-failure-just-case