By Amy Tennery
NEW YORK (Reuters) - Several Republicans took to social media Wednesday to declare they will never back Donald Trump for U.S. president even after Ted Cruz, the billionaire businessman's closest rival, dropped out of the race for the party nomination.
The anti-Trump declarations came from a range of quarters, including at least one Republican U.S. senator and a number of political commentators who have been leading voices of the #NeverTrump movement that has resisted his candidacy.
Trump's victory in the Indiana primary on Tuesday prompted Cruz's surprise decision to suspend his campaign and left Trump a largely uncontested path to securing the roughly 200 delegates he still needs to lock down the Republican presidential nomination for the Nov. 8 election.
"Reporters keep asking if Indiana changes anything for me. The answer is simple: No," U.S. Senator Ben Sasse of Nebraska said on Twitter. Sasse included a link to a February Facebook post in which he appealed to Trump backers to drop their support.
Mark Salter, a former speech writer for Senator John McCain, said he would support former Secretary of State Hillary Clinton, the leading candidate for the Democratic nomination, over Trump.
"The GOP is going to nominate for President a guy who reads the National Enquirer and thinks it's on the level. I'm with her," Salter (@MarkSalter55) tweeted, referring to a common rallying cry among Clinton supporters.
But the high-profile "Stop Trump" or "Never Trump" effort launched by conservative Republicans failed to significantly slow Trump's momentum and appeared not to have achieved its mission as the date nears for the Republicans' convention in July.
After Trump's Indiana victory on Tuesday night, Republican National Committee Chairman Reince Priebus called for the party to back Trump.
"@realDonaldTrump will be presumptive @GOP nominee, we all need to unite and focus on defeating @HillaryClinton #NeverClinton,” Priebus (@Reince) tweeted.
Still, it was clear that Trump faces some difficulty bringing all Republicans on board.
Bill Kristol, a neoconservative and editor of the Weekly Standard, offered a scathing retort to former House Speaker Newt Gingrich's call to back Trump.
"If you're for Trump you functionally are for a man unfit to be president, & for the degradation of [American] conservatism," tweeted Kristol (@BillKristol) early Wednesday.
"Never ever ever Trump. Simple as that," tweeted Tim Miller (@Timodc), former campaign communications director for Jeb Bush, who dropped out of the White House race earlier this year.
Several Republican voters said on Twitter that they were changing their party affiliation, while some posted photos of their voter registration cards lit ablaze.
(Reporting By Amy Tennery; Additonal reporting by Michelle Conlin and Steve Holland; Editing by Dan Burns and Frances Kerry)