Four months before the initial voting, Paul is having such a big impact on the race that some Republican operatives are convinced that he will play spoiler in important states, siphoning votes and attention from his rivals for months to come and helping determine the nominee.
He's empowered by unconventional but successful fundraising techniques, a more sophisticated campaign than his two previous attempts at the presidency, and a fiery message he's preached for decades but only now is resonating with Americans concerned about the nation's debt.
In short, he could prove dangerous for the early front-runners, Texas Gov. Rick Perry and former Massachusetts Gov. Mitt Romney.
"I have no idea what exactly spoiler means," Paul said recently while in New Hampshire. "If you're a participant and you have an influence and you win or come close and you influence the debate, I think that's pretty important. So I don't put a negative term on that as spoiling anything. Spoiling their fun? Maybe they need a little spoiling."
It's unclear which rival the 76-year-old Texan stands to hurt the most.
Paul's most devoted followers have been committed to him for years. But the "converts," as the congressman calls them, seem to be growing with little regard for whether their support of Paul unintentionally helps another candidate.
Kate Baker is among the many die-hard Paul supporters in New Hampshire who shrug off the suggestion that their candidate may play spoiler. She holds out hope of victory.
"Ron Paul is doing well enough he has the possibility to win, particularly in key states. This time I can taste success," said Baker, the volunteer head of New Hampshire's Women for Ron Paul Coalition. She also worked to help Paul get elected four years ago.
But for Baker and others, winning almost sounds less important than spreading Paul's message of fiscal discipline and smaller government. That's a pitch he's made for years and one that others suddenly have adopted, sometimes with more success.
"Look at how much the message is traveling right now. He's honest and consistent. That's the kind of person I can put my money and effort behind," said Baker, a 37-year-old Manchester resident. "I vote for Ron Paul on principle."
Others like her have helped Paul build a grass-roots fundraising network so robust that his team is preparing for a primary campaign that goes the distance, confident Paul will raise enough money to stay in the race as long as he wants.
His fundraising prowess dropped jaws four years ago when, during one cash-grab blitz, he raised more than $5 million in 24 hours. Drawing on thousands of small online donations, Paul has raised at least $1 million in five individual "money bombs" this year, according to his campaign.
Overall, he raised $4.5 million this year through June 30 and is expected to report $5 million more through the end of September. That's well behind Romney and probably Perry, too. But it's far more than most of the second-tier candidates.
It's not just money that's helped him become a more credible candidate this time around. It's also the improved quality of his campaign.
Paul moved more quickly this year to put organizers and experienced workers in important states. He was the first candidate to run television ads in New Hampshire. At the straw poll in Ames, Iowa, a test of campaign organization, Paul finished second to Minnesota Rep. Michele Bachmann by only 152 votes.
"The fact that we have so many county chairmen and precinct chairmen and all this all through Iowa, we never had that before," Paul said recently from his office in Washington.
There are signs that Paul is adopting more traditional, and possibly successful, campaign strategies, according to Eric Woolson, who managed former Arkansas Gov. Mike Huckabee's victory in the 2008 Iowa caucuses. The strong straw poll finish was "maybe a little more of an acknowledgement that this is the way the game is played," he said.
In New Hampshire, the difference goes beyond organization.
Paul still talks freely about some subjects that place him on the fringe, such as ending the fight against drugs. But his early ads in the state seemed to "recast" his image, said Richard Killion, an unaffiliated Republican strategist who had advised former Minnesota Gov. Tim Pawlenty, a 2012 race dropout, in New Hampshire.
The ads give the impression that Paul is the most electable and best positioned to beat Obama, going against the conventional wisdom that Paul "speaks out well on big problems in Washington, but may not be the best messenger to tackle them," Killion said.
Paul is working to remedy that perception.
"I keep thinking maybe how I can improve on saying things so the people can understand what I'm talking about and make sure that they don't misinterpret me," he said.
All this suggests Paul is poised to improve upon his 2008 performance, when he grabbed more than 7 percent in the New Hampshire Republican primary and reached as high as 14 percent in Nevada.
"There's no doubt in my mind that Ron Paul will get somewhere north of 10 percent, possibly even in the high teens, which will have a major effect and impact on the race and who wins -- whether its Perry or Romney -- in New Hampshire," said Michael Dennehy, a New Hampshire-based operative who led Sen. John McCain's campaign four years ago.
"I would go so far as to say he will play spoiler," Dennehy said. "I do not see his support waning below 10 percent."
Paul also seems more willing to mix it up with the other candidates that he was in 2008.
He acknowledges trying to score political points that raise his profile in addition to his standard no-frills discussion of the issues.
A Paul television ad calling Perry "Al Gore's Texas cheerleader" garnered loads of attention and drew attacks from Perry. That was an unusual reaction from a front-runner who would typically ignore attacks from lesser candidates.
Paul said he wrestles with how to apply the new style.
But as much as other candidates pull Paul's ideas into the conservative mainstream, it's easy to forget he was the Libertarian Party's candidate for president in 1988.
Paul calls for immediate withdrawal of troops around the world, brushes aside concerns about Iran obtaining a nuclear bomb and has suggested Israel be left to defend itself. He would return to the days when the currency was backed by gold. He would eliminate a host of federal agencies and says, "There is no greater threat to the security and prosperity of the United States today than the out-of-control, secretive Federal Reserve."
Mostly, Paul is pleased that some ideas he's hammered for years are echoing all around him.
"Nobody ever did this and now it's not just me doing this," he said. "I think that's all good."