Republican In Name Only (RINO) is a disparaging term that refers to a Republican candidate whose political views are seen as insufficiently conforming to the party line.
The phrase, without the RINO acronym, became first popularized during the Theodore Roosevelt presidency, as he was often labeled a “Republican in name only” by both critics and proponents, as his trust-busting policies were at odds with long-standing Republican Party ideologies.
By 1992, the acronym “RINO” had shown up in print, with an article in the New Hampshire Union Leader, written by John Distaso, being cited as the first instance of RINO in print.
“The Republicans were moving out and the Democrats and ‘RINOS’ (Republicans In Name Only) were moving in.”
The use of the term RINO arose as polarization increased in the political parties. Prior to the 1992 election of Bill Clinton, the Democratic and Republican parties had been in a long process of realignment where conservative Democrats and liberal Republicans were quite common. With the election of Bill Clinton, Republican ideological unity became increasingly fixed. This is exemplified by Grover Norquist’s Taxpayer Protection Pledge, which called upon signatories to reject and oppose all measures to increase tax rates. By 2012, nearly every Republican presidential candidate was a signatory to this pledge.
The increasing ideological unity of the Republican Party made holdovers from the previous political alignment look like outliers. Whereas historically liberal Republicans comprised a wing of the Republican Party, they had (by 1992, and especially by 2020) become incompatible with the Republican Party itself.
Therefore, in an age of party unity, the term RINO was often used as a political weapon. It could be used as a threat: vote how your party wants or be branded a RINO. It could also be used as an effective tool in a primary campaign: the incumbent is a RINO, vote for the challenger. Indeed, in the 2010 Congressional Elections, the Tea Party effectively used the term RINO as a way to “primary” Republican Incumbents whose policies were not conservative enough.
RINO is also related to the historical term “Rockefeller Republican” which referred to (traditionally) Northeast Republicans who championed business friendly practices while remaining relatively socially liberal. Named after Nelson Rockefeller who served as the Governor of New York before running unsuccessfully for the Republican Presidential nomination in 1960, 1964, and 1968. This term has largely died out as the Rockefeller family’s political successes have dwindled.