It's been a lousy couple of weeks for Matt Bevin.

Matt Bevin (R). (Luke Sharrett/For The Washington Post)

Senate Minority Leader Mitch McConnell's Republican primary challenger dealt with fallout from the revelation the he once backed a government program he uses as a punching bag. Then he stoked controversy with remarks about gay marriage. It all came as McConnell continued to avoid the pitfalls that have ensnared some of his Senate colleagues facing heat from the right.

The result is that with three months until the primary, Bevin's bid to defeat McConnell faces increasingly long odds.

"He's having some trouble," said veteran political observer Al Cross, a former Louisville Courier-Journal political writer.

Bevin, a Louisville businessman, was veered off message after a Wednesday interview on Janet Mefferd's radio show in which he suggested legalizing gay marriage could lead to parents being able to marry their children.

"If it's alright to have same-sex marriages, why not define a marriage -- because at the end of the day a lot of this ends up being taxes and who can visit who in the hospital and there's other repercussions and things that come with this -- so a person may want to define themselves as being married to one of their children so that they could then in fact pass on certain things to that child financially and otherwise?" Bevin asked.

That prompted top McConnell aide Josh Holmes to declare "The return of Akin-ry," a reference to controversial and failed 2012 Senate candidate Todd Akin (R).

Bevin was sidetracked last week by the revelation that he backed the TARP program as an investment fund president in 2008, even as he rails against the federal bank bailout initiative these days. The news prompted McConnell's allies to cast him as a hypocrite.

The mounting Bevin problems have arrived as McConnell, while unpopular in Kentucky, has run a steady race. He's raised money at a fast pace and avoided the kind of eyebrow-raising stories that have plagued other longtime Republican senators facing voters this year.

McConnell was forced to swallow a politically sour pill last week when he cast a key procedural vote to advance legislation to raise the nation's debt ceiling. But Kentucky conservatives reacted with a collective yawn, arguing that it didn't change the balance of those Republicans who are for him versus those who are against him.

It's a rare day when a sitting senator goes down in defeat in a primary. So extraordinary, in fact, that it's only happened eight times in the past 30 years. It often takes a perfect storm of exceptional campaigning from a challenger, a deeply unpopular incumbent and missteps from the incumbent and/or the incumbent's campaign.

So far, only one of those items has been checked off in Kentucky: The one about McConnell's struggling image. Bevin's been a lackluster campaigner. And McConnell has avoided the you-know-it-when-you-see-it moments that have swiftly hamstrung other senators facing primary threats.

For example, Sen. Thad Cochran (R-Miss.) recently said he doesn't "really know a lot about" the tea party. Sen. Pat Roberts (R-Kan.) revealed that he pays a modest monthly rent to stay with supporters when he is Kansas, as opposed to living in the house he owns.

McConnell hasn't made the same kind of blunders.

Still, Bevin and his allies remain upbeat. They point to McConnell's unpopularity to argue that he isn't electable enough against likely Democratic nominee Alison Lundergan Grimes. And they say there is time to make up ground against McConnell ahead of the May 20 primary. One recent poll had the GOP leader up 26 points.

The final six weeks are the "most crucial," said Bevin consultant Mark Harris, who added that he was confident Bevin would have the financial resources necessary to compete down the stretch.

Bevin and his allies are trying to drive home the idea that a generic Republican can and should win the general election but McConnell is too damaged for that task. But Bevin's stumbles mean he isn't a generic Republican with a clean slate. And polls show he isn't a decidedly stronger candidate against Grimes compared to McConnell.

"I think [Bevin's] probably a pretty nice guy, but I don't think he's going to begin to carry the day," said Jim Weise, a veteran Kentucky GOP operative who is backing McConnell.

In this case, the nice guy could finish last in the race between him and McConnell.