WASHINGTON — Congressional Republicans are beginning to accept, and even embrace, an outcome that was once unthinkable: Donald Trump as the GOP presidential nominee.

In the wake of the businessman’s commanding wins in five Eastern states this week, a growing number of lawmakers say that Trump is taking on an air of inevitability. Some argue they should get behind him now instead of trying to stand in his way, as some establishment Republicans are still attempting to do by backing various “Never Trump” efforts.

For some lawmakers, supporting Trump is seen as their only hope of stopping the Democrats’ likely candidate, Hillary Clinton, in November and ensuring a Democratic president doesn’t fill Supreme Court vacancies.

“I don’t understand. I mean, it’s not ’Never Trump.’ It’s ’Never Hillary.’ Never, never, never, Hillary. Come on. Wake up and smell the coffee,” said Rep. Mike Kelly of Pennsylvania, who earlier this week cast his ballot for Trump, along with all members of his large family and 57 percent of Republican primary voters in his state.

“I’ve never seen a party attack one of its own candidates with this aggressiveness,” Kelly said of GOP establishment figures who oppose Trump, blaming it on an elitist Washington attitude out of touch with voters.