Republicans say they know to what to expect from Marco Rubio as he prepares for Florida’s Aug. 30 Senate primary: Even if he’s a Johnny-come-lately to the race, they’re confident he has the built-in skill and resources to once again become a formidable candidate.  

They’re less certain about what to make of Rubio’s stubborn new rival, Carlos Beruff.  

The Miami developer’s surprising refusal to leave the primary — he was the only one of five major Republican candidates who stayed in the race — has complicated Rubio’s re-election bid.  

Instead of quietly making amends with party regulars and raising money before the general election, Rubio faces a two-month sprint to fend off a first-time candidate who hasn’t been shy about throwing elbows at the lawmaker.  

[

Roll Call’s 2016 Election Guide: Senate

]  

But how much Beruff could threaten Rubio is hard to know, say Republicans watching the race. He could tap into the anti-establishment fervor that has propelled Donald Trump, but he doesn’t have the presumptive GOP nominee’s celebrity.  

He could draw a potent contrast between his business background and Rubio’s career in politics, but he might not have enough time to make that case before the primary.  

And although he says he plans to spend his own money to help his cause — as much as almost $20 million — Republicans say they’ll be waiting and watching to see if the promised spending surge ever actually comes.

A ‘Trumpian-style thing?’

“You gotta ask yourself, does he really have the resources to mount the campaign, or is this just another Trumpian-style thing?” asked Rick Wilson, a Florida GOP strategist who had been working on the race before Rubio’s return.  

[

‘Little Trump of Florida’ Says He’s Not Like Trump

]  

Skepticism over how much Beruff plans to spend increased last week, when he filed an extension to report his wealth . It was the second such extension the candidate had requested.  

Beruff has said he plans to spend between $10 million and $15 million to defeat Rubio, on top of the roughly $4 million he had spent boosting his candidacy before Rubio changed his mind on seeking re-election.  

In an interview, he said that he would “spend whatever is necessary to get to the end of this race.”  

“I have always had resources committed to this race, so long as I felt that the public liked what I had to say and what I stand for,” Beruff said. “And I will continue down that path.”  

He undoubtedly starts the primary as an underdog: A poll released last week from the Associated Industries of Florida showed him trailing the senator by more than 60 points.  

[

Consultants Sticking With Beruff Despite Rubio Run

]  

But Beruff and his advisers, who haven’t left him despite Rubio’s presence in the race, say they can win over a Republican electorate that only a few months ago chose Trump over the home-state senator by nearly 20 points in the presidential primary.

Trump coattails

They have consciously tried to tie Beruff to Trump’s campaign, even saying that he would gladly speak at the Republican National Convention in Cleveland if invited. Rubio recently said he won’t speak on Trump’s behalf at the convention.  

[

Analysis: Why Rubio’s Return is Good, Not Great News for the GOP

]  

“It’s amazing to me, most of the political pundits have some degree of amnesia,” said Curt Anderson, a GOP strategist. “They can’t grasp the fact that three months ago, Rubio won one of 67 counties in Florida and got a quarter of the votes. Now they see him as a prohibitive favorite.”  

Recent Florida political history would suggest Beruff’s challenge isn’t impossible. Gov. Rick Scott beat the odds against an establishment-backed fellow Republican candidate in 2010, the same year Rubio himself defeated the favored former Gov. Charlie Crist in the GOP Senate primary.  

Beruff, a Miami native, invites those comparisons, painting himself as the principled outsider against a Washington insider out for himself.  

“Marco Rubio will not even commit the next six years to doing the job of a senator,” Beruff said. “That tells you a lot. It tells you exactly why he’s staying in this race and why he continues to go for the limelight … to stay relevant.”  

[

Senate GOP Candidate: Florida Voters Don’t Want Rubio

]  

Both Beruff and Rubio have even less time to prepare for the primary than the Aug. 30 date for voting would suggest. The first absentee ballots for military personnel overseas go out July 15, and early voting begins Aug. 15.  

Rubio allies say they are confident that the senator can rely on the political infrastructure he has built since taking office in 2011 to quickly assemble a strong campaign. They’re also confident that he can count on an armada of outside groups and super PACs to run TV ads while he refills his campaign coffers.  

Florida is a big, expensive state, and some GOP strategists say that even the money Beruff is pledging to spend might not be enough to even raise his name recognition sufficiently.  

“In order to make a dent, an unknown candidate would have to spend millions and millions each week just to get their name ID up,” said one GOP strategist supporting Rubio. “Senator Rubio doesn’t have that problem.”  

Contact Roarty at alexroarty@cqrollcall.com and follow him on Twitter @Alex_Roarty.