Rockefeller, a leading contender for the 1964 nomination, was considered a likely nominee four years later, until Richard Nixon's campaign surged through the primaries. Reagan, elected California governor in 1966, was already looked upon as a future presidential prospect (he announced his own candidacy for president on the eve of the convention, withdrawing when it became clear that Nixon had the delegates). This button suggests a possible alliance between the liberal Republicans who supported Rockefeller and the conservatives who backed Reagan.