Presumptive Republican presidential nominee Donald Trump cruised to victory in two more states Tuesday, while Bernie Sanders beat rival Democrat Hillary Clinton in West Virginia to bolster his argument for remaining in the race. The substantial wins in West Virginia and Nebraska according to early results put Trump ever closer to clinching the 1,237 delegates he needs to be declared the party's nominee at its convention in July. Now the sole Republican candidate in the contest after his remaining rivals dropped out last week, Trump is transitioning from the fierce primary battles with the likes of Ted Cruz and Marco Rubio to a general election showdown with Clinton, even amid deep Republican discord about the celebrity billionaire.

Trump challenges

While Clinton still has Sanders to worry about, Trump faces a rebellion within the Republican leadership over the insulting tone and shifting substance of his candidacy.

House Speaker Paul Ryan last week announced he was "not ready" to support Trump, a rare rebuke that put the power struggles within the Republican Party on very public display.

Ryan and other Republican congressional leaders were due to huddle with Trump Thursday in Washington, in highly anticipated meetings that could help gauge GOP support for the real estate tycoon.

McConnell said he expected "a cordial meeting to discuss the way forward."

It may be thorny. A defeated Cruz ruled out a third-party bid, but when pressed by reporters as he returned to the US Senate he declined to say whether he would endorse Trump.

Rubio said he would "support the Republican nominee" but would not offer an outright endorsement.

The Republican establishment is still reeling from Trump's hostile takeover of the party, aghast at positions he's taken on trade, foreign policy and taxes that fly in the face of conservative dictums.

But Trump has shown no sign of backing down, and some Republicans are looking to heal, embrace the nominee and turn to defeating Clinton in November.

"I think the party needs to come together," said Senator John McCain, the 2008 Republican nominee