This record was cut in 1952, at the heightening of Cold War sensitivity. The candidates were Republican Dwight D. Eisenhower and Democrat Adlai Stevenson. Incumbent Harry Truman was expected to get the democratic nomination, but the lumps he’d taken over the Korean War loomed large in the public mindset. Eisenhower capitalized on this, and his own decorated military background. He promised, if elected, he’d go to Korea and end the war himself.
It worked. The Eisenhower/Nixon ticket mopped the floor with Stevenson/Sparkman, winning 39 of the 48 states.
What was the greatest Presidential drubbing of all time? The election of 1936.