Louisville, Kentucky (CNN) -- The Kentucky State Fair has its share of eye-popping choices:
*Deep fried Kool-Aid
*The Donut Burger, a heart-stopping marriage of Krispy Kreme and quarter pounder.
*And this year, at the 50th annual Farm Bureau Country Ham Breakfast, a have to see it to believe it pairing: former foes Mitch McConnell and Rand Paul side by side, all smiles, eager to prove the Republican establishment and the tea party cannot only coexist, but can be allies.
It wasn't too long ago that Paul, a freshman senator, was a thorn in McConnell's side -- defeating the Senate Republican leader's candidate of choice in the 2010 primary season that helped put the tea party on the map.
As Paul surged late in that campaign, McConnell cut an ad for his choice, Kentucky's then-secretary of state.
"I know Trey Grayson and trust him. We need Trey's conservative leadership to help turn back the Obama agenda," McConnell said in the spot.
Fast forward three years, and what you see is an awkward alliance that is in part the product of painful lessons McConnell has learned in recent years as tea party backed insurgents have knocked off GOP establishment figures in primaries, including one of McConnell's best friends in the Senate, Robert Bennett of Utah.
At the State Fair event, McConnell delivered a forceful rebuke of President Barack Obama's health care plan.
"The solution to Obamacare is to pull it out root and branch." McConnell told the breakfast moment's after Kentucky's Democratic governor praised the plan.
McConnell, though, opposes a tea party backed plan to risk a government shutdown if that is what it takes to deny the president the funding necessary to implement the health care program.
It is one of the issues highlighted by McConnell's tea party backed primary opponent, businessman Matt Bevin. And one of the issues where Team Mitch, as his campaign calls itself, hopes having tea party favorite Paul in his corner helps blunt Bevin's appeal.
"I think it is a dumb idea to shut down the government," Paul said in response to a question from CNN as he and McConnell met with reporters recently at the fair.
The Bevin challenge is a case study in Tea Party 101. The litany of familiar complaints against the establishment rattled off in one early Bevin TV ad:
"McConnell has voted for higher taxes, bailouts, debt ceiling increases, congressional pay raises, and liberal judges."
Bevin's chances likely depend on some big outside help, and some of the conservative groups who make their names taking on the GOP establishment are dipping their toes into the race now to get a sense of whether McConnell is truly vulnerable.
"Career Washington politician Mitch McConnell claims to be a conservative," is the opening line of one recent radio ad paid for by the Madison Project.
The Kentucky primary is May 20, and given the early bruising tone, plus McConnell's national profile, there is no doubt this contest will shatter state spending records for Senate races.
The matchup here is one of several testing the standing of veteran, establishment Republicans. GOP Sens. Lindsey Graham of South Carolina and Lamar Alexander of Tennessee, for example, are bracing for potentially tough challenges. Liz Cheney is running against incumbent GOP Sen. Mike Enzi in Wyoming.
McConnell's campaign recently released its own polling showing a more than 40 point lead over Bevin. But he is running as if scared, mindful of the tea party surprises these past two election cycles.
McConnell is already spending on TV ads, painting Bevin as a political opportunist.
"Bevins' company failed to pay taxes, then got a taxpayer bailout. Bailout Bevin, not a Kentucky conservative," blares one.
Another focuses on a Bevin resume that appeared to suggest he graduated from Massachusetts Institute of Technology when, in reality, he participated in a short MIT seminar program for which all recipients received a certificate.
"Newspapers say Bevin was dishonest about his resume -- claiming to graduate from prestigious MIT," this McConnell ad declares. "Not true."
Some see evidence of McConnell's caution in the Syria debate now front and center in Congress. Of the four top leaders in Congress, McConnell is alone in not supporting the president's call for military strikes: GOP House Speaker John Boehner, House Democratic leader Nancy Pelosi and Senate Majority Leader Harry Reid are all on record backing action.
McConnell issued a statement Tuesday saying he was still undecided.
"Congress and our constituents would all benefit from knowing more about what it is he thinks needs to be done — and can be accomplished — in Syria and the region," the GOP leader said after a White House meeting with the president.
McConnell aides say his caution has nothing to do with the campaign.
But Bevin is on record opposing military strikes against Syria, as is Paul -- and to take a position at odds with his primary rival and new ally would instantly make the Syria debate a campaign flashpoint.
Democrats were already on record promising to make McConnell a top 2014 target, even though Kentucky hasn't elected a Democrat to the Senate since Wendell Ford won his last six-year term in 1992.
Secretary of State Alison Grimes is well aware of the history, and using her early months of the campaign to try to make the case she would be no rubber stamp for Obama.
"We have had trouble in our state identifying with the national Democratic Party," Grimes said in an interview. "I will tell you I am running as a Kentuckian. ... I have my disagreements with the president."
Chief among them, she says, is an energy policy she called anti-coal. Grimes also favors changes to the health care law, but says it has many admirable pieces that should be kept.
She is campaigning, at least for now, as someone who expects McConnell to survive the primary challenge.
"It's about ending the disease of dysfunction that we have seen in Washington, D.C.," she says of her campaign. "And after nearly 30 years, Senator McConnell is at the center of it. He is to blame for the failed leadership."
McConnell's team labels Grimes as too liberal for the state and suggests the president's standing here would be a major drag.
But the incumbent himself prefers not to deliver direct blows, just yet, leaving that, for the most part, to his team and TV ads.
"I like a good campaign," McConnell said after the fair breakfast. "We are going to have a lot of fun."