Paul Singer, the billionaire super PAC moneyman, likes Marco Rubio just fine — but he’s not quite ready to crack his seven-figure checkbook for a shoestring Rubio campaign run out of a tatty Capitol Hill row house.

Like just about every Republican these days, Singer — who accrued a $2 billion fortune through a famously cautious investment strategy — is wondering if the ascendant 44-year-old Florida senator can really create a big-time national campaign, said two people familiar with the hedge fund manager’s thinking.


It’s not clear whether Singer grilled Rubio about his campaign when the two men supped in New York earlier this month, but in the past he’s aired concerns about the scope of the senator’s political operation and fundraising operations, the sources told POLITICO.

Seldom has a candidate running around 9 percent in national polls (in third place, a click or two ahead of Jeb Bush) generated as much buzz as Rubio has heading into the third Republican primary debate Wednesday night in Boulder, Colorado. And he’s not into the buzz, at least not yet: Rubio is a candidate who prioritizes self-preservation over an early surge in the polls — overseeing a campaign geared at protecting him from being eaten alive as the latest establishment standard-bearer.

“We only need to be in first place for one f--king day,” said one Rubio staffer, who hopes his man peaks — at earliest — in December, with just enough momentum heading into Iowa and New Hampshire.

That’s why Rubio has adopted a small-mammal approach, maneuvering quietly at ground level, hoping that dinosaurs like Donald Trump, Jeb Bush and Ben Carson ignore him while stomping each other into extinction.

Therein lies his paradox. To gain stature — and attract enough donors to be competitive in the first four make-or-break contests — Rubio needs to aggressively promote himself, but not so aggressively that he becomes a focal point of the race.

The think-small strategy isn’t just a matter of dodging incoming fire: Another person close to the campaign said that Rubio had counted on more cash early on — but opted to steer much of his war chest to travel, in the belief that the energetic, articulate candidate would be the campaign’s best kick-starter. That means small operations in battleground states and a focus on relatively cheap social media and volunteer recruitment.

“If you are still standing in May, running smaller or leaner now is going to look very smart. If you are out, not so much,” says Chip Felkel, a South Carolina GOP consultant who is skeptical of Rubio’s decision. “Rubio's team has prided themselves on this lean approach, and on their commitment to digital rather than boots on the ground. They are making a pretty gutsy bet that you don't need a presence anywhere except online. That may make your campaign more agile, sure, but I am not sure that equates to strength.”

Henry Barbour, an influential Republican National Committee member in Mississippi, says he thinks the debates are critical for Rubio — if he continues to impress, the cash will start rolling in, allowing Rubio to hire the staff needed to go national.

“Jeb is running a big, robust campaign built to go the long haul with more depth in March primary states than other campaigns,” says Barbour. “On the other hand, the Rubio campaign is smaller and has been less aggressive building out. For Rubio to win, it will be because he keeps performing well." With two debates coming up in the next two weeks, "If he can continue his strong debate performance, he will have more cash and volunteers to smartly ramp things up.”

Of course, all of this means Rubio’s under-the-radar days are numbered. Indeed, they will likely end as soon as Wednesday night, when Rubio will become a target of well-defined attacks unlike anything he’s seen in the past two debates, several rival campaigns told POLITICO.

Already his enemies have begun to converge months ahead of his staff’s plans. Bush’s team, for its part, earlier this week leaked a puckish PowerPoint presentation to donors labeling Rubio a “GOP Obama.” And he’s been the target of a spate of nasty yarns about his staff’s stiletto tactics.

Democrats are increasingly viewing him as a threat, and it’s clear why. Republicans, who have lost the popular vote in five out of the past six presidential contests, need someone to bridge the widening gap between the battered but rich establishment wing of the party and dominant but general-election-challenged tea party wings. At the moment, Rubio appears to be the only candidate with a foot in each of those warring worlds.

The Democratic National Committee has begun targeting him for missing dozens of votes — and his claim that he’s done so because he “hates” the Hill. The danger for Rubio is that his opponents tap an existing reservoir of skepticism on the right fueled, in part, by his abortive immigration reform effort in 2013.

Moreover, Rubio — a restless young-man-in-a-hurry with a not-insignificant opinion of his own gifts — raised eyebrows recently, telling The Washington Post that he’s missed a third of recent Senate votes because he’s not running for reelection. One person close to him said that he’s had to be repeatedly restrained from taking shots at front-runner Trump (Rubio called Trump’s campaign a “freak show” after the reality TV star labeled Rubio a “clown” — a quip one person close to Rubio cited as a rare breach of discipline).

Rubio’s team doesn’t want to see a similar outburst at the debate, and has counseled the boss to keep his temper in check as the other candidates try to knock him down. Things could get nasty whether he wants them to or not: Many Rubio advisers, who have watched as Bush’s team attacked him on Twitter in recent weeks, are convinced that Bush will target his onetime Florida ally.

Four people who’ve spoken with Rubio in recent weeks say he feels little desire to strike back, convinced that getting dragged into a slap-fight with his onetime friend will do little to help him. Rubio, they say, is determined to stay above the fray and believes that other candidates are only hurting themselves as they collide with rivals. One friend said Rubio — who had faced criticism from Bush’s supporters that now wasn’t his time to run for president — has shed no tears watching the former governor flail.

There’s one other reason to lay off Bush: One person close to Rubio said doing so would hurt efforts to win over the elder Floridian’s donors, who are disappointed in the former governor but still like Bush personally. The wooing is already underway. Earlier this month, Rubio and his advisers gathered a group of top donors at the Bellagio in Las Vegas for a two-day event of political briefings. In between games of touch football with the senator, donors strategized about poaching some of Bush’s contributors.

That hasn’t happened yet — and the proud penuriousness of the Rubio campaign is, to some extent, an effort to make a virtue out of necessity. His hard-money fundraising — the tightly regulated cash his campaign raises for its operations and advertising — has been middling, less than $15 million as of the third quarter.

In response, Rubio’s campaign manager Terry Sullivan modeled the 2016 game plan on Rubio’s underfunded, insurgent 2010 Senate race — with an eye on John McCain’s come-from-behind victory in the 2008 GOP primaries.

No other GOP campaign is so self-consciously penny-pinching: Sullivan recently vetoed a request from a field organizer in Indiana who wanted a few hundred Rubio for President baseball caps – until the staffer could quantify how many volunteers he could sign up; He eventually agreed to pay the bill. Sullivan, a ruddy and combative former Rubio Senate staffer who favors jeans and checkerboard Vans slip-ons, is utterly obsessed with the campaign’s outflows. He’s intent on keeping the campaign’s burn rate in the 40 percent range, compared to a typical campaign’s rate of expenditure which averages about 60 percent of cash raised – or Bush’s 86 percent burn rate for the third quarter.

Sullivan, people close to him say, has prioritized social media outreach over labor-intensive door-knocking, and volunteer recruitment over hiring statewide staff — all cost-saving measures. Compared with Bush, Rubio is fielding relatively small statewide operations — with no more than a half-dozen or so paid staffers (plus volunteers) in each Iowa and South Carolina. Bush has around double that number in each state.

Whether this is genius or folly depends on Rubio’s ability to generate enough volunteer enthusiasm to make up for the lack of in-state staffing, as Barack Obama did in 2008. “A smaller operation means you don’t have to raise as much hard money, but it could pose challenges to organizing states like Iowa and New Hampshire,” says veteran GOP strategist Carl Forti, who helps run the Karl Rove-founded American Crossroads super PAC.

Sullivan has told donors he has no plans to hire more than a handful of new staffers over the next few months. But that could change if Rubio really catches fire on the fundraising front, as he clearly hopes to do.

His opponents aren’t impressed. “Rubio’s campaign is making an unpredictable and risky bet that traditional campaign organizing doesn’t matter — one dimensional campaigns rarely if ever succeed — and no one in their right mind should cede control of their efforts to forces you can’t control,” said one top aide to a Rubio rival.

Yet the low burn-rate mantra isn’t just a practical necessity — it’s become a major pitch point to donors, especially those turned off by the comparative profligacy of the free-spending Bush campaign. Earlier this month, Sullivan and ad man Todd Harris stood before a room of more than 90 bundlers at the downtown D.C. office of Akin Gump, a powerhouse Washington lobbying firm, to tout their paleo-diet campaign. Sullivan argued that a big staff didn’t necessarily guarantee a win — a jab at the faltering Bush, who paid more than $4.6 million on salaries to staffers and consultants between July and September more than four times what Rubio has spent.

All this coupon-clipping chatter masks more conventional ambitions: For all his struggles to raise campaign cash, he has excelled at collecting big, soft-money checks from heavyweight super PAC donors. Rubio’s PAC has raised over $16 million, third behind only Bush and Cruz — and he’s closing in on securing a genuine juggernaut contributor — Las Vegas casino magnate Sheldon Adelson. The two have grown increasingly close in recent months, bonding over their shared background as sons of immigrants and their love for Israel.

Sources close to Adelson — who contributed over $100 million to Republican candidates and causes during the 2012 election — say he’s close to getting on board with Rubio, with an endorsement as soon as the end of this month.

And for all the talk of seeking the safety of middle-pack, Rubio clearly relishes the day when he will become a true front-runner, as dominant in the polls as he’s become in the online political prediction markets. In mid-October, the candidate gathered around 20 of exiled Wisconsin Gov. Scott Walker’s top bundlers for a get-to-know-Marco roundtable at the offices of Weil Gotshal & Manges, a white shoe law firm on Fifth Avenue. During the meeting — which drew, among others, financial players Jonathan Burkan, Eric Anton,and Julian Gingold — Rubio offered a fierce-urgency-of-now rationale that belied his campaign’s stated strategy of patience.

“No one’s ever dropped out of a presidential campaign because they ran out of ideas,” one person present recalled him saying. “They dropped out because they ran out of money.”

It apparently worked: After the roundtable, Rubio held a fundraiser in the same building that brought in over $350,000.