FILE - In this June 23, 1948, file photo, delegates with posters and state signs crowd down the center aisle at Convention Hall in Philadelphia during a demonstration for Gov. Thomas E. Dewey after his name was placed in nomination during the Republican National Convention. It was 1948 when Dewey won the Republican presidential nomination on the third ballot of a contested convention in Philadelphia. Months later, he lost the general election to Democratic incumbent Harry S. Truman. Could a real contested convention happen again, 68 years later? (AP Photo/File)