The party “nominally” aligned with the GOP is the New Progressive Party. While many of its members are aligned with the GOP, many prominent members are national Democrats (such as ex-Govs. Pedro Rosselló and Carlos Romero Barceló, along with the current Resident Commissioner, Pedro R. Pierluisi).
Frustratingly, when the Republican-aligned ex-Governor, Luis Fortuño, ran on the 2008 and 2012 tickets, he excitedly endorsed Democrat Pierluisi (who won even as Fortuño lost). Had Pierluisi lost, he would’ve been replaced with, yup, a member of the Popular Democrats, meaning still another Democrat (although the Populares actually oppose statehood). To put it simply, the GOP didn’t even have a candidate running for the sole federal office... it was a race between two Democrats.
Aside from Fortuño’s single win in 2008, the last Republican to win the Governorship was Don Luis Ferré in 1968 (despite the Progressive Party winning on some other occasions since, but again, ALL its other Governors were Democrat-aligned, as were the Popular Democrats and its new Governor, a Populare). Those two men were the sole Republicans to win the Governorship since the popular vote was instituted in the 1940s.
In effect the provincial Liberal Party was the conservative party in local politics, and Jean Charest, a Conservative Party leader in national politics, like didn't have much choice but to become a Liberal when he wanted to run for Premier of Quebec.
FWIW, Charest also had birth certificate troubles, as his legal birth name was "John" rather than "Jean."
If Puerto Rico were to become a state the anomalies would iron out and it would become a pretty solidly Democrat state.
you are always on the mark