Senate Minority Leader Mitch McConnell, R-Ky., has big plans for next year if he gets to lead a Republican majority, but he has to avoid losing his own seat first.

McConnell is the only Republican whose Senate campaign is on the RNC's 2014 watch list. A new Rasmussen poll suggests why.

"McConnell runs dead even with Democratic challenger Alison Lundergan Grimes in Rasmussen Reports' first look at the 2014 U.S. Senate race in Kentucky," Rasmussen says. "But McConnell's GOP primary rival Matt Bevin leads Grimes by six points."

Bevin, a political newcomer, is the rough equivalent of putting "Generic Republican" on the ballot. In Kentucky, Generic Republican beats the Democratic secretary of state by six points. McConnell is not a generic Republican, though. In a general election, moderate and left-leaning independents know him as the senator who said his top goal was to make President Obama lose re-election (a line that Obama's team cited repeatedly last year). For all that he's accused of conservative extremism and partisan hackery, conservatives also don't trust him, regarding him as the face of the Republican establishment.

He still has a big lead in the Republican primary. Public Policy Polling, a Democratic-leaning firm, showed McConnell with a 53-26 lead over Bevin in December. Human Events, a more conservative outfit, produced similar results last month, when McConnell enjoyed a 53-31 lead over Bevin.

Even those polls show signs of weakness for McConnell. PPP found that only 31 percent of voters approve of his job performance, compared to 61 percent who disapprove. Those numbers track with the Human Events survey of Republican voters. Human Events didn't ask about overall job performance, but -- given the Republican electorate's opposition to Obamacare -- a question about whether McConnell has done enough to fight the health care law seems like a good proxy. Fifty-nine percent of Republican voters polled told Human Events that "McConnell is not doing enough to end Obamacare."

McConnell's recent focus on the IRS scandal could endear him to the Tea Partiers who were targeted during the 2012 election.

"McConnell is now putting pressure on John Koskinen, the new IRS Commissioner, to withdraw a proposed regulation that would make the targeting and harassment of government critics a permanent feature of the tax agency's regulatory processes," the Washington Examiner's Mark Tapscott pointed out Monday morning.

A 30-year senator can only do so much to change voters' impressions of him in the middle of an election year, though. Bevin's capacity to define himself as a conservative alternative to McConnell remains the real question mark.

PPP seemed skeptical in December. "He remains mostly unknown to Republican voters in the state -- 61 percent don't have an opinion about him one way or the other," the polling firm noted. "And the voters who do have an opinion about him don't particularly like him -- just 14 percent see him favorably to 25 percent with a negative opinion. GOP voters say they like Rand Paul better than McConnell by a 59/27 margin, but so far they're not seeing Bevin as someone in the Paul vein."

Those numbers might reflect Team Mitch's work to define Bevin unfavorably, but they also could show the downside of how "Bevin speaks more like the businessman he is than a fire-breathing conservative; stylistically, he's more Mitt Romney than Ted Cruz," as Politico put it.

National Review noticed a comment from Bevin that seems to back up that observation. “We have way too much partisanship in Washington,” Bevin said. “And it shouldn't be a function of, you know, the Democrats are this, therefore the Republicans have to be opposed to it or vice versa. It's got to be what's in the best interest of this country. Shutting down the government is ridiculous.”

Mitch McConnell couldn't have put it better himself. The upside of having a Mitt Romney-like business background? Bevin is a wealthy candidate. In addition to the support of the Senate Conservatives Fund, Bevin can put a lot of money into the race if he has to, in order to define himself as the conservative alternative to McConnell.

"We absolutely will be on air, both through radio, through internet, through TV, in a substantive way," Bevin told Politico. "There will be nobody who goes into the voting booth on May 20 that does not have an informed opinion of who I am, I can assure you of that."

It's hard to imagine a Senate leader losing a re-election bid. The last time that happened was in 2004 when Democratic leader Tom Daschle of South Dakota was defeated by Republican John Thune -- and that was the first time since 1952.

Senate Majority Leader Harry Reid, D-Nev., who succeeded Daschle, was the most unpopular senator in the country (that title now belongs to McConnell, according to PPP) when he survived in 2010. The most likely outcome is that McConnell wins this primary and hangs on in the general as the national political environment trends against Democrats.

For Bevin to win, he'll have to run a perfect campaign, and he'll probably still need McConnell — a veteran campaigner — to make a couple of mistakes. If that happens, as unlikely as it seems now, McConnell could lose this primary.