KANSAS CITY, Kansas – The bus – emblazoned with the faces of Kansas Republican candidates – rolled into the Kansas Speedway parking lot on an unbearably frigid Friday afternoon to a pack of reporters, TV cameras and sign-wielding volunteers and supporters.  Willie Nelson’s “On the Road Again” played while the assembled crowd waited.

Finally, out came the pair of GOP candidates facing defeat in ruby-red Kansas, flanked by star Republican surrogates. Both the embattled incumbents face the prospect of defeat on solidly Republican turf -- and have run tough campaigns focused on making sure the natural partisan order reasserts itself. There was Gov. Sam Brownback, who has had to deal with very public rejection by some members of his own party, in his own state. And incumbent Sen. Pat Roberts -- the man who, despite the lack of a major party opponent, has found himself cast in the role of campaign underdog.

A parade of national Republican names descended on Kansas this year -- some of them staffers dispatched to stabilize the flailing Roberts campaign behind the scenes, others to stand beside him at events like this one. These are the people who were tasked with bringing home the conservative base crucial to a Roberts victory -- and now, in the home stretch, the moderate Republicans he'll need to hold on to his job.

And so, as he’s rolled into communities over recent weeks with his all-star retinue, Roberts has stuck to two prime messages: that Greg Orman is a liberal in disguise who will be a rubber stamp for President Obama and Harry Reid.

And that this race is about more than Pat Roberts – it’s about the very control of the U.S. Senate.

“Tying [Orman] with Obama and Reid, it’s almost like a guilt thing: Kansas, don’t screw it up for the rest of the country,” said Clay Barker, Kansas State Republican Party Executive Director. “We need a Republican Senate.”

And yet the race remains a pure tossup, as Roberts fights for his political life.

“The one thing I want to impress upon you is, Number One, I’m going to win this race,” Roberts said outside the speedway on Friday. “The road to a Republican majority in the United States Senate is running right through Kansas. You have a very clear choice: you have a conservative Republican, a fourth-generation Kansan… and somebody who is going to be working with the Republican majority to stop the Obama agenda. My opponent is just the opposite.”

Heading into the final days, the Roberts campaign feels fairly confident that they’ve shored up the conservative base they’ve been going after -- it’s the moderate Republicans they are turning to now. On Sunday, Roberts will embark on a two-day state tour starting in voter-rich Johnson County, an area that's roughly 30 percent independent with even fewer Democrats -- and, most of all, a significant moderate Republican presence.

The campaign unveiled ads touting the incumbent's record on agriculture issues and an endorsement from beloved Kansas State University coach Bill Snyder, who calls Roberts a “dear friend.” (That has since become a campaign issue in of itself, as has a comment from Orman referring to Roberts’ bus campaigning as a “Washington establishment clown car.")

On the stump, Roberts has been making a nod to his Marine roots. Marines “have an expression: to err is human, to forgive it divine. Neither is Marine Corps policy,” he told the Kansas City crowd, to laughter. “We are going to take this hill.”​