LOUISVILLE, Ky (WHAS11) -- One week after his Republican National Convention speech attempted to unite separate wings of the GOP, U.S. Sen. Rand Paul is warning that third party candidates could derail Mitt Romney's quest for the presidency.
Paul cited Libertarian candidate Gary Johnson's potential impact in the New Mexico and Nevada races and Constitution Party candidate Virgil Goode Jr's shaving votes from Romney in the Virginia race.
"Virginia could make a difference because Virginia is going to be very tight," Paul (R-KY) said. "If the Constitution Party gets four or five percent, that could be enough for the Republicans to lose."
Goode is a former six-term Congressman and state legislator.
Paul declined to call for Johnson, a former Republican New Mexico Governor, to drop out of the race.
"It's a free country," Paul said. "We have rules on getting on to the ballot. It's actually difficult to get on the ballot."
Paul said Romney needs to react to the third party challenges.
"If you're the nominee of the party, you need to appeal to those people who are either Libertarian or Constitutional conservatives," Paul said. "You need to say, 'Stay in the party because I am going to be sincere about balancing the budget. I am going to be sincere about cutting some spending.' It's going to take some work to keep those people in the party."
Supporters of Paul's father, Texas Congressman Ron Paul (R), may need some extra convincing. Unlike Rand Paul, the libertarian Republican has refused to endorse Romney. The former presidential candidate was declined a speaking role at the GOP convention where the Republican National Committee stripped convention seats from some Ron Paul delegates.
Despite the rift between his father and the party, Rand Paul is calling on Ron Paul supporters to back Romney, explaining it is mutually beneficial.
"I want them to stay in the Republican Party, because I think they have more influence in the Republican Party," Rand Paul said.
"For example, if the Tea Party were to break off into its own party, I think it would have less influence and actually would just defeat the Republican candidate."
"I think if you believe in things that aren't quite what the Republicans are doing, try to pull the Republicans in your direction and I think we are winning a lot of those battles," Paul said, citing a handful of his priorities placed into the Republican platform.
"Audit the Fed is in there, setting the gold standard is in there, my bill on drones is supported in there, that you can't have drone surveillance without a warrant," Paul explained.
Paul said Democrats' dominance on the West Coast and in New England makes a Republican win "tougher and tougher" in the electoral college because "once you give up all those votes, then you got to win pretty much the rest of the country."
"That's one of the messages I've had to the national Republican party. You know what, those areas where you are not competing? Maybe a libertarian Republican would do better in California or New York State."
Paul complimented a "very personable" Michelle Obama's speech at the Democratic National Convention.
"I think a lot of times, it gets lost on the public that politicians are just these hardened people who don't have families," Paul said, "And so I think it was a good speech from that perspective."
In very personal terms, the First Lady's speech connected her husband's politics to her family's experience, stressing that Obama administration policies aim to help the middle class.
"I think the problem with their theme is that they think they can punish the rich to help the middle class. I think when you punish the rich, you hurt the middle class. If you punish the rich, you hurt the poor."
Paul told WHAS11 he's ready to campaign for Mitt Romney, but the campaign has not set any specific dates.