 <unk> route to the Republican Party 's presidential nomination , Nixon faced challenges from Governor George Romney of Michigan , Governor Nelson Rockefeller of New York , Governor Ronald Reagan of California , and Senator Charles Percy of Illinois . Nixon won nine of the thirteen state primaries held that season , although due to the population of his state , Governor Reagan won the popular vote while carrying only California . These victories , along with pledged delegate support from states not holding primaries , secured Nixon the nomination on the first ballot of the Republican National Convention , where he named Governor Spiro Agnew of Maryland as his running mate . 
