Princeton professor Paul Starr, writing in the New York Times, describes the disappearance of the center right:
Mr. Trump's purges continue the Republican march to the right that began in the 1980s. At that time, many leading Republicans were economically conservative but socially liberal or moderate. Often from elite backgrounds, they called for balanced budgets, free trade and other pro-business policies, while also supporting abortion rights, racial inclusiveness, immigration reform and environmental protection. Republicans had little hope of congressional majorities without them. But as the center of gravity in the party shifted south and west, the moderates became a dwindling and dispensable minority, increasingly forced to adapt to the new orthodoxy or to quit the party.
In the Senate, for example, the group of Republican moderates in the Wednesday Club, which had nearly two dozen members in the 1980s, had shrunk to five by 2008. Three of them — Lincoln Chafee, Jim Jeffords and Arlen Specter — became Democrats or caucused with them. Olympia Snowe retired, and Susan Collins, the last one in the Senate, may just have sacrificed her reputation as a moderate with her immoderate speech endorsing Brett Kavanaugh....The center right has not disappeared, but it has had its home in electoral politics taken from it...
The root of the problem of the center right is that it lacks a base in popular politics. The combination of economically conservative and socially moderate views does not match up today with the large blocs of voters who identify with either the Democratic or the Republican Party. The support for that hybrid position lies mainly among the affluent and especially the leaders of corporate America.
That's why America today is not a center-right country.
It seems misleading to focus on the Senate without mentioning the governor's offices, where the center-right is alive and well in the persons of Charlie Baker, Republican of Massachusetts, and Larry Hogan, governor of Maryland. Meanwhile, in New Jersey, where, last I checked, Princeton is situated, the candidate running for Senate as a Republican, Bob Hugin, is doing so as a supporter of New Jersey's gun control laws, a supporter of a path to citizenship for "dreamers," and as " pro-choice, pro-marriage equality." Maybe the Republican or Democratic parties don't match the economically conservative, socially moderate model, but that profile does attract enough independent voters to, in some states, translate into election victories.