The rise of such non-traditional Republican presidential hopefuls as Donald Trump, Ben Carson and Carly Fiorina ¡ª all non-politicians ¡ª has many political pundits insisting the 2016 election is unique. But the truth is exactly the opposite: The GOP is on a well-worn path, followed since King Primary replaced King Convention as the preferred method for selecting presidential nominees.

Republican voters, as opposed to party power-brokers, began effectively picking the party¡¯s presidential nominee in 1964. Conservative populist Sen. Barry Goldwater of Arizona upset the establishment favorite, New York Gov. Nelson Rockefeller, in the defining California primary. Since then, GOP presidential-primary outcomes fall into three distinct and fascinating results:

1) Every sitting Republican president eligible to seek another term won re-nomination: Richard M. Nixon in 1972, Gerald Ford in 1976, Ronald Reagan in 1984, George H.W. Bush in 1992 and George W. Bush in 2004.