It's been a good few weeks for Rand Paul. In some recent polls of the 2016 Republican primary, Paul has led the race or tied with Mike Huckabee, who seems unlikely to run. A recent Washington Post story described his burgeoning "50-state network." And at US News, David Catanese dubbed Paul "the current GOP frontrunner" because of his consistent polling performance and his apparent strength in early states.

But Paul isn't the GOP frontrunner. He's not even close. Those who say otherwise are watching the wrong numbers.

"I would completely discount the polls right now," UCLA professor Lynn Vavreck told me. "It's too early. Nobody knows who's officially in the race and who isn't."

Consider this: not one Republican hopeful has managed to amass 25 percent support in any poll conducted so far. The small swings in the polls are interesting trivia, but they're occurring among a tiny population of potential voters — and, worse, a population that is unusual in both ideology and enthusiasm. The bulk of people just aren't paying attention yet. They need to weigh in before the media begins crowning frontrunners based on polling.

The invisible primary is the process during which party leaders, insiders, and donors decide which candidate to support.

At this point, more important than the polls is what political scientists call "the invisible primary." This is the process during which party leaders, insiders, and donors decide which candidate to support.

Unlike polls, the invisible primary mostly occurs behind closed doors — though sometimes it can be quite conspicuous, as with last week's visits by potential contenders to casino billionaire Sheldon Adelson, the top Super PAC donor in 2012. Rather than polls, Vavreck said, "I would look at who the party leaders seem to be gravitating toward." This will winnow the field and help determine which choices the voters eventually are presented with.

And the key voters in the invisible primary are paying attention now. Insiders know that they'll end up with more influence if they manage to pick the winning candidate early. The question political scientists are obsessing over is how they're making that decision.

According to Hans Noel, a professor of government at Georgetown, party leaders care about two main things — whether a candidate is electable, and whether the candidate's positions and profiles are appropriate for the party. "They don't want someone who's less electable, or who would do things the party doesn't want done," says Noel.

Paul has problems on both electability and on fitting with the GOP's platform. First, Paul has had associations with some less savory members of the right, which could call his electability into question. The Washington Free Beacon reported last year that one of Paul's aides "spent years working as a pro-secessionist radio pundit and neo-Confederate activist," and the aide soon resigned. Second, Paul still holds some positions that are extremely controversial within the party. For instance, he's called NSA leaker Edward Snowden a "civil disobedient," and in 2009 he mused that Vice President Dick Cheney could have backed the Iraq War to benefit the company Halliburton, an argument frequently mocked by Republicans.

There's one main reason to believe Paul will be an important force in the primaries — his formidable fundraising.

Noel said that Paul wasn't necessarily a strictly "unelectable" candidate, but that it's Republican party leaders who will decide whether his positions and associations are acceptable. "It really is the party experts who can conclude, 'Yeah, we've decided the Rand Paul flavor of foreign policy libertarianism is the direction this party is gonna go,'" Noel said.

But that doesn't seem to be happening. The Washington Post reported last month that many GOP donors and insiders, "alarmed by the steady rise" of Paul, are working to convince former Florida Governor Jeb Bush to join the race. "People trying to convince Jeb Bush to run, that's exactly the invisible primary dynamic we're talking about," Noel told me. "When McCain ran the first time [in 2000], he was on record supporting things the party didn't want. If they see Rand Paul as a similar threat, they're going to do what they have to do to stop him."

A good example of this dynamic is the 2012 Republican primary. Before the voting began, Republican primarygoers kept handing the poll lead to candidates who the party considered dangerously unelectable, like Herman Cain and Newt Gingrich. So party support concentrated behind Romney. That helped give Romney the money, the organization, and the endorsements needed to outlast the rest of the field.

So despite the polls, Paul will remain an underdog unless he somehow manages to convince many Republican insiders that he should be their standard-bearer. But there's one main reason to believe he'll be an important force in the primaries — his formidable fundraising. "Campaigns never end because people want campaigns to end. They end because they run out of money," chief Romney strategist Stuart Stevens said last year.

And in our age of newly-empowered outside money and Super PACs, even one rich and motivated donor can prolong a campaign for months. Vavreck said that in 2012, "Santorum and Gingrich stayed in the race through February, March, and April because they each had a big outside donor giving them checks for millions of dollars." Under previous rules capping donors' contributions, they would have had to drop out months earlier. So while Paul may be no front-runner, he's well-positioned to cause heartburn for whoever the front-runner turns out to be.