It was once Paul D. Ryan’s party, built on the union of upright Middle American values and America’s competitive advantage in the world.

Now it’s Donald Trump’s — the nationalist, me-first team, willing to compromise on character, foreign policy and free-market economics if it brings a win.

In modern times, the Republican Party operated hierarchically before Trump. The presidential nominees were the obvious ones.

That changed in 2016 when Ryan, the obvious choice, the party’s young, energetic ideas man and its 2012 vice presidential candidate, declined to run, and Trump defeated a slate of vanilla alternatives to seize the nomination and the presidency.

Perhaps Ryan’s emotional announcement on April 11 that he will not seek re-election in 2018 is the prelude to a 2020 primary challenge. The Never Trumpers could be plotting a comeback, and who could doubt that in his heart, Ryan — who once said Trump “sickened” him — is one?