What are the most popular political buttons?

Kennedy campaign buttons are the most popular, followed by Reagan and then Truman.

Among those, Truman buttons are the most rare. Not many were made because everyone thought Dewey would win the election. But Truman traveled the country and won over the popular vote.

By the way, the famous "Dewey Defeats Truman!" front page from the Chicago Tribune that Truman held up after his victory is one of the most valuable newspapers among collectors. A copy of that paper in excellent condition is worth $1,000 or more.