In September Paul was as high as third in opinion polls behind former Massachusetts Gov. Mitt Romney and Texas Gov. Rick Perry. While Georgia businessman Herman Cain was in the top three in a Washington Post-ABC News poll, Paul still captures double-digit support -- a far cry from the scant 3 percent in his 2008 campaign. A RealClearPolitics.com average of polls indicates Paul polls an average of 7.7 percent.
Paul handily won the recent Family Research Council's Values Voter Summit straw poll for GOP presidential candidates, with the socially conservative crowd ranking him ahead of Cain and former U.S. Sen. Rick Santorum of Pennsylvania, who placed second and third.
A Family Research Council leader, however, told CNN Paul is an interloper who influenced results of the Voter Values poll by busing supporters to the event.
"I think Ron Paul, when you look at everything, is an outlier in this poll," Tony Perkins said. "You see Herman Cain finishing a strong second, followed by Rick Santorum, Michele Bachmann and Rick Perry. Those are more reflective, I think, of ... the other polls and what's happening in the social conservative community."
"He's run before and he'll run again," said political commentator Steven Schier, a political science professor at Carleton College in Northfield, Minn. "He is a cause candidate. He's running to get the Libertarian agenda out for the public to inspect."
Paul, who ran for president in 1988 as a Libertarian, has a fervent following, but hasn't been able to expand much beyond that niche, Schier said.
In the 2008 campaign, Paul struck a nerve with voters, who seemingly couldn't get enough of him, turning out in droves for his speaking engagements and book-signings across the country.
Paul raised $8 million in the last quarter, less than the front-runners but certainly enough to keep him competitive, The Dallas Morning News reported.
Paul's stanch message about small government and free markets has gained legs amid concern about the rising government debt and health of the economy. Once considered a party eccentric because of his views, Paul, 76, now finds others embracing his opposition to the existence of the Federal Reserve Bank, the income tax and foreign aid.
Observers said he's doing something right to get his message heard more broadly despite his sometimes eye-glazing topics.
"When he goes to the general public and starts speaking about the Austrian school of economics, I'm afraid that some people just stop listening," Iowa Republican state Rep. Jason Schultz, head of the local chapter of Farmers for Ron Paul, told The Washington Post.
This cycle the Paul campaign is working to increase his visibility on the stump and on television. Paul has made nearly two dozen trips to Iowa since declaring his candidacy in May, compared with nine such visits in a similar period in 2008. Paul's TV commercials have been airing in four early primary states since July. By comparison, in 2007 he didn't start advertising on TV until the end of the year.
The campaign also is trying to diversify Paul's base, reaching out to groups such as farmers and evangelicals, and running a TV ad promoting Paul's stints as a surgeon in the Air Force and in the Air National Guard.
"He serves as an anchor to the right that will have a Romney or a Perry appealing more to Libertarian bases," said Ron Christie, a GOP strategist who served as a special assistant to President George W. Bush and is unaffiliated this year. "They will not want to be outflanked by him."
Paul's presidential Web site says the Pennsylvania native and obstetrician-gynecologist "never votes for legislation unless the proposed measure is expressly authorized by the Constitution" and is, as characterized by former Treasury Secretary William Simon, the "one exception to the Gang of 535″ on Capitol Hill. He favors limited constitutional government, low taxes, free markets and a return to monetary policies based on commodity-backed currency (read: the gold standard).
Paul and his wife Carol are the parents of five children, including U.S. Sen. Rand Paul, R-Ky., elected in 2010.
His reliance on the Internet -- witness his so-called money bombs online fundraising efforts -- also attract a youthful audience.
"I've been waiting for this election cycle, praying that he would run, and he did," Drake University sophomore Ben Levine told the university's student newspaper, The Times-Delphic.
Levine, the campus president of the Young Americans for Liberty, said Paul gets "so much coverage on the Internet [that] it's unbelievable. Internet media is where he shines, and youths are attracted to that."
"A lot of people say Ron Paul is extreme," Levine said. "If he's extreme, then peace, keeping the money you earn, protecting life and adhering to the Constitution is extreme. In that case, I'm extreme and so are a lot of people."
Perkins acknowledged Paul's campaign taps into the discontent "with big ineffective government that's taking place in this country … . The message his campaign is sending is something other campaigns have to listen to as well."
Paul drew applause and criticism for saying during a Republican contenders debate in Tampa, Fla., that government is not responsible for a hypothetically uninsured individual in a coma and needing medical care.
"That's what freedom is all about, taking your own risks," he said. "This whole idea that you have to prepare and take care of everybody ... ."
Asked if he was saying society should let the patient die, Paul said: "No. I practiced medicine before we had Medicaid, in the early 1960s … [and] and the churches took care of them [the uninsured]. We never turned anybody away from the hospitals."
The applause kept coming when Paul said, "And we've given up on this whole concept that we might take care of ourselves and assume responsibility for ourselves."
In a commentary and in speeches recently, Paul denounced the U.S. drone strike in Yemen that killed Anwar al-Awlaki, the U.S.-born al-Qaida figure.
The president, Paul said during his National Press Club appearance, "can now assassinate people without due process -- American citizens. And people cheer it. What is going on with this country?" The Dallas Morning News reported.
He maintains President Obama could be impeached for ordering the strike while conceding that most of his colleagues on Capitol Hill don't share his view.
The goal of a free society, Paul told the Values Voter Summit, is to "seek virtue and excellence."
"And only we as individuals can do that. When we turn this over to the government, when we seek our king and depend on our king, it can only be done at the sacrifice of liberty," Paul said. "And that means eventually all liberties … [are] always under attack."
Besides saying he wouldn't have ordered the deadly attacks on Osama bin Laden and Awlaki, Paul espouses a government that has no authority to regulate recreational drugs, prostitution or same-sex marriage. He's against foreign intervention and favors a gold standard.
"He's not running to get nominated," political observer Schier said. "He's running to keep the Libertarian agenda out for public inspection."