Einstein 1954 - one great mistake in my life

According to R. Clark, in November 1954 - five months before his death - Einstein said:

• "I made one great mistake in my life... when I signed the letter to President Roosevelt recommending that atom bombs be made; but there was some justification - the danger that the Germans would make them." quoted in Ronald Clark, Einstein: The Life and Times, pg. 752 

Source: http://www.doug-long.com/einstein.htm

Letter: Letter from Albert Einstein to President Franklin D. Roosevelt: 08/02/1939.