TAMPA, Fla. — Almost embarrassed out of politics by his presidential run, Sen. Marco Rubio has made a remarkable turnaround, and now is poised to win a second term in the U.S. Senate — along the way also transforming himself from tea party hero to establishment favorite.
The same Republican voters who overwhelmingly rejected him in Florida’s presidential primary in March, ending his run and possibly his political career, now herald him as the savior of the GOP’s Senate majority.
“He’s not old enough to run for president and he’s not skilled enough to run for president, but we need him to keep the Senate,” said Edith Wessner, 70, a registered Republican who cast her early-voting ballot Tuesday for Mr. Rubio and Republican presidential nominee Donald Trump at a public library in South Tampa.
Republicans have grown increasingly confident about a Rubio victory over Democrat Patrick Murphy, which is vital to their effort to save the thin 54-seat majority in the 100-member Senate amid fears that Mr. Trump is damaging the party’s down-ballot candidates.
The Democratic Party, although its congressional campaign arm withdrew financial support of the Murphy campaign last week, remains confident that a Senate takeover is within reach thanks to new targets popping up.
In the final weeks of the campaign, Democrats have targeted races that were not competitive before Mr. Trump shook up the electorate map to the detriment of Republicans.
Democrats are eyeing defeats of once relatively safe Republican Sens. John McCain in Arizona, Roy Blunt in Missouri, Richard Burr in North Carolina and Daniel Coats in Indiana, where GOP vice presidential nominee Mike Pence is governor.
Mr. Rubio, whose fierce primary fight with Mr. Trump devolved into trading insults, has stuck by his endorsement of the New York billionaire. But Mr. Rubio has distanced himself from Mr. Trump, whose faltering campaign prompted widespread defection from GOP leaders.
In the same way, Trump voters said they remained loyal to Mr. Rubio.
Mr. Murphy, a second-term congressman whose southeast Florida district stretches from Ft. Pierce to Palm Beach, has aggressively argued that Mr. Rubio is closely tied to Mr. Trump, blasting him for not pulling his endorsement.
“Despite calling Trump a ‘con man’ during their presidential primary days, Rubio has endorsed Trump as the Republican nominee. Even after women came forward to share their stories of Donald Trump’s sexual assaults, Rubio continues to stand by him,” the Murphy campaign said in a statement this week as Mr. Trump made a campaign swing through the state.
The Murphy campaign asked when Mr. Rubio would appear beside Mr. Trump.
Mr. Rubio never joined him on the stump.
The attack mostly threatened to undermine Mr. Rubio’s efforts to woo Democrats and independents.
“If he hadn’t gone with Trump, I probably would have voted for him,” said independent voter Bill Young, 64, a retired businessman. “Was on the fence, and that was the deciding factor.”
Meanwhile, Republican voters gave Mr. Rubio a pass on his realignment from tea party to party establishment.
“In my opinion, he hasn’t change so much. He got railroaded in the primary,” said Matthew Berning, 51, a retired U.S. Air Force technical sergeant who voted early for Mr. Rubio in Valrico, Florida, a fast-growing community about 15 miles east of Tampa.
After winning his Senate seat as a tea party champion in 2010, Mr. Rubio often broke with conservatives, most conspicuously when he joined the bipartisan “Gang of Eight” senators who proposed amnesty for illegal immigrants as part of a comprehensive immigration bill.
That helped pigeonhole him as an establishment figure by the time he ran for the White House, while Mr. Trump’s populist campaign eclipsed the tea party and conservative movements.
Following his washout in the presidential race and a belated run for re-election to the Senate, Mr. Rubio more fully embraced GOP establishment positions, such as abandoning fiscal restraint to back spending $1.1 billion taxpayer dollars to fight the Zika virus without budget offsets.
“He’s not a real conservative. But he’s better than the totally nonconservative, communistic Democrats,” said Edward Gato, who voted for Mr. Rubio in Valrico.
The 72-year-old retired Army captain acknowledged that Mr. Rubio had changed since his tea party days.
“He’s mellowed out a little bit. He’s not as angry as he should be,” said Mr. Gato. “He’s learned how the system works, and he’s using it.”