A growing number of Republicans are vowing not to support Donald TrumpDonald TrumpTrump to undo Obama's climate change agenda Kushner met Russian bank executives: report Trump tweets: 'Trump Russia story is a hoax' MORE for president even if he wins the party’s nomination.
Trump racked up a number of wins on Super Tuesday, bringing him closer to being the GOP standard-bearer.
But some Republicans say they cannot support the real estate mogul under any circumstances.
Sen. Ben Sasse (Neb.) became the first lawmaker in the upper chamber to vow not to vote for Trump, saying he would instead search for a third-party contender.
In an open letter to Trump supporters posted on his Facebook page, Sasse claimed that while many who are backing the front-runner are “well-meaning,” he cannot get behind a candidate focused on “tearing down rather than building back up this glorious nation.”
Across the Capitol, Reps. Reid RibbleReid RibbleWith Trump, conservatives hope for ally in 'War on Christmas' GOP rushes to embrace Trump House stays Republican as GOP limits losses MORE (Wis.), Mark Sanford (S.C.), Carlos Curbelo (Fla.) and Scott RigellScott RigellGOP rushes to embrace Trump GOP lawmaker appears in Gary Johnson ad Some in GOP say Trump has gone too far MORE (Va.) are also refusing to back Trump.
And the opposition isn’t just on Capitol Hill.
Massachusetts Gov. Charlie Baker told reporters after Super Tuesday that he won’t vote for Trump.
A number of prominent pundits are also vowing to not back Trump, including Fox News contributor Erick Erickson.
This story was last updated on March 9 at 3:16 p.m.
Republicans who won't back Trump
Gov. Charlie Baker (Mass.)
Glenn Beck, conservative host
Jay Caruso, RedState
Eliot Cohen, former George W. Bush official
Rep. Carlos Curbelo (Fla.)
Steve Deace, conservative radio host
Rep. Bob Dold (Ill.)
Erick Erickson, conservative writer
Rep. Richard Hanna (N.Y.)
Doug Heye, former RNC communications director
Former Rep. Bob Inglis (S.C.)
Matt Kibbe, former Freedom Works CEO
Bill Kristol, The Weekly Standard editor
Kevin Madden, former Mitt Romney aide
Former RNC Chairman Mel Martínez (Fla.)
Liz Mair, GOP strategist
Former Gov. George Pataki (N.Y.)
Former Rep. Ron Paul (Texas)
Rep. Reid Ribble (Wis.)
Former Gov. Tom Ridge (Pa.)
Rep. Scott Rigell (Va.)
Rep. Mark Sanford (S.C.)
Sen. Ben Sasse (Neb.)
Former Rep. J.C. Watts (Okla.)
Peter Wehner, conservative New York Times contributor
Former Gov. Christine Todd Whitman (N.J.)
--Read more from The Hill: