Mr. Cannon was a war correspondent in Korea and an editor and vice president of Newsweek before joining the staff of Gov. Nelson A. Rockefeller of New York in 1969. After Rockefeller was appointed vice president in 1974, Mr. Cannon accompanied him to Washington as an aide. In 1975, Ford named Mr. Cannon a presidential assistant and executive director of the White House Domestic Policy Council. It was in that capacity that Mr. Cannon called Mayor Abraham D. Beame of New York that May, interrupting him at a political dinner — he had been cutting into a filet mignon — to tell him that the administration would not help his financially reeling city. Mr. Cannon and his deputy, Richard L. Dunham, wrote the letter flatly denying any aid to the city. Months later, Ford underlined the message in a speech, inspiring the memorable headline in The Daily News: “Ford to City: Drop Dead.” In November, he reversed himself, signing legislation allowing $2.3 billion in short-term loans to the city. John Myers Cannon was born on Feb. 26, 1918, in Sylacauga, Ala., and grew up in Athens, Ala. He changed his name to his father’s, so he could be James Monroe Cannon III. He graduated from the University of Alabama and served in the Army and the Office of Strategic Services in World War II. He was a reporter at several newspapers before joining The Baltimore Sun, for which he covered the Korean War. Mr. Cannon went on to be a writer and editor at Time magazine and to hold top editing and executive positions at Newsweek before becoming an aide to Governor Rockefeller on Congressional matters. Mr. Cannon worked on Ford’s losing presidential campaign in 1976. He then moved on to be chief of staff to Howard H. Baker Jr., the Republican leader in the United States Senate. When Mr. Baker became chief of staff to President Ronald Reagan, Mr. Cannon helped him analyze White House operations. Mr. Cannon is survived by his wife, the former Cherie Dawson; his sons James and Scott; and two grandchildren.