Ledyard King

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WASHINGTON — GOP Sen. Marco Rubio’s biggest roadblock to re-election might not be a Democrat.

It might be Republican Donald Trump.

While presidential candidates usually breathe wind into the sails of downballot candidates, analysts say Trump could be a drag on Rubio’s chances of winning a second term in November.

The billionaire’s approval rating falls considerably beneath the senator’s in numerous Florida surveys. And while recent polls have Rubio up several points on likely Democratic opponent Rep. Patrick Murphy, Trump trails Democratic presidential nominee Hillary Clinton by a similar margin in a state considered key to control of both the White House and the Senate.

Florida's Senate primaries will take place on Tuesday. Rubio is expected to defeat Manatee County developer Carlos Beruff in the GOP contest, and Murphy is expected to defeat Rep. Alan Grayson to win the Democratic nomination.

Trump trounced Rubio in Florida’s presidential primary March 15 after the two exchanged personal attacks on the campaign trail.

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Rubio called Trump a “con man” who couldn’t be trusted, and Trump disparaged his rival as “little Marco” and a “dishonest lightweight.”

Rubio has since decided to back Trump while still emphasizing their many disagreements on policy. And Trump has gotten behind Rubio’s decision to break his earlier pledge not to run for re-election.

A Monmouth University poll released earlier this month found nearly two-thirds of Florida voters are unaware Rubio has backed Trump for president. Of those who are aware, seven of 10 said Rubio’s support for the real estate mogul makes them less likely to back the senator for re-election.

“Republican incumbents who have distanced themselves from Trump appear to be doing better than those who haven’t,” said Patrick Murray, director of the Monmouth University Polling Institute, pointing to Ohio Sen. Rob Portman. “That could potentially be a problem in a tight race for Marco Rubio.”

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Tallahassee lobbyist Brian Ballard, who recently raised money for Rubio and is Trump’s finance chairman in Florida, doesn’t view Trump as an obstacle for the senator.

“Marco has his own brand that appeals to a broad swath of Florida voters,” he said. “I think he’s working hard, running his own campaign and smartly positioning himself as his own candidate. He’s telling people to vote for Trump but he’s also talking about why the Senate matters, why he matters, and I think it will resonate.”

Florida is a mix of positives and negatives for Trump.

He lives there part time, has numerous real estate projects and is friendly with Gov. Rick Scott. But his controversial comments about Hispanics have alienated large segments of a key voting bloc in the state. And his bombastic treatment of presidential rivals, including Rubio and former Florida governor Jeb Bush, left some Sunshine State Republicans fuming.

Many have made peace with Trump. The chairs of county Republican parties across the state have endorsed him. Party activists and GOP donors generally have gotten behind him to varying degrees, united in a mission to defeat Clinton.

Still, some Rubio backers harbor doubts about Trump.

Maurice Mandeville, a Satellite Beach Republican who gave Rubio $250 three days after he announced his re-election bid in June, isn’t completely sold on the real estate mogul — at least yet.

“I’m getting there,” said the Air Force veteran and retired computer technician for the City of Vero Beach. “I don’t want to see Clinton win anything (but) I’m a little leery of what Trump has been doing. He’s like a loose cannon. You never know when his gun is going to go off in the wrong direction.”

John Lillich, a Rubio donor from Palm City, said Republicans waffling on Trump need to get on board quickly.

“They better start getting some enthusiasm or they’re going to blow this election,” he said.

Nathan Gonzales, editor and publisher of the non-partisan Rothenberg & Gonzales Political Report, said recently that Trump’s presence on the ballot “could be an anvil around (Rubio’s) neck.”

It’s hard to measure exactly how much danger Trump's presence at the top of the GOP ticket poses for Rubio.

Conservative Hispanics in Miami-Dade who form a key GOP pillar aren’t expected to abandon a native, Cuban-American son they’ve supported in the past simply because the presidential nominee has made inflammatory comments about Latinos.

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In the March 15 presidential primary, Trump won 66 of 67 counties, sending Rubio out of the race. Rubio’s lone bright spot was Miami-Dade, where he won 63% of the vote.

On the other hand, Rubio could suffer backlash from Trump backers unhappy that he hasn’t fully embraced the nominee.

Beruff, Rubio’s primary opponent and an ardent Trump backer, has slammed the senator for his “tap dance” on the presidential nominee. But Rubio is so far ahead of Beruff in polls, he hasn’t had to worry about any ill will Republican voters might harbor for his muted backing of Trump.

Tamping down his support for Trump would serve Rubio well in the November election, Murray said. That’s why the Monmouth University pollster expects Democrats will make a big deal of it after Labor Day.

“The fact that most voters don’t know that Rubio said he supports Donald Trump is something that Murphy can use in a general election,” Murray said. “There is some definite potential there that could be a drag on Rubio.”

Is it Trump or Clinton?

Elections 2016 | USA TODAY Network