Most Kansans would probably think that the very definition of a safe Senate seat is that of Pat Roberts. The three-term senator has won every election he contested and has never earned less than 60 percent of the vote. Roberts is also a respected voice in the Senate, with history as chairman of the Intelligence Committee.

Roberts likely will win again, but is facing three challenging realities that might make his 2014 re-election effort his toughest yet.

First, Roberts lost his senior position on the Senate Agriculture Committee. Membership shifts put a more senior Republican on the panel, which took Roberts out of his ranking minority spot. First District Congressman Tim Huelskamp was removed from the House Agriculture Committee, providing a convenient parallel, except for the fact that Huelskamp's removal was retaliatory while Roberts' was procedural.

Still, the senator might find struggle to fundraise as agricultural interests look to the new senior Republican, Mississippi's Thad Cochrane. Robert's age could work against him as well -- if re-elected the Senator will be 84 at the end of his next term.

Second, according to a recent Public Policy Polling survey, Pat Roberts is the second-most anonymous senator in the country. More than 40 percent of Kansans surveyed could not identify Roberts, placing him ahead of only first-term Illinois Sen. Mark Kirk. Public Policy Polling was one of the most accurate pollsters in 2012, giving the findings weight. Roberts can take solace in the facts his approval numbers were higher than disapproval, and other elected officials in the state have even lower numbers.

Gov. Sam Brownback's approval stands at just 37 percent, yet he appears poised to cruise to re-election as Democrats continue to lack a candidate around whom to rally in 2014. Another Roberts advantage lies in that there is no likely Democrat to challenge him in the general election.

Roberts' third, and toughest, challenge is the possibility of a primary opponent on the right. Club for Growth, emboldened by victories like the Kansas primary purge of moderate Republicans last year, has taken that model to Congress, soliciting names of moderate Republicans in the House to recruit competitors against.

Unlike the 2012 primary lead-up that happened quietly, the next phase of their attempted purge will be very public. The group recently launched PrimaryMyCongressman.com, where voters can submit the name of their Republican member of Congress for a primary challenger. The website doubtless will serve as a public invitation for conservative candidates to emerge across the country. An aggressive, self-described conservative might decide to ride that wave into a challenge for Roberts' seat.

According to the PPP poll, just 42 percent of Republicans would vote to renominate Roberts today, against 34 percent that would prefer someone more conservative.

Despite a recent rightward shift, particularly in response to the Benghazi attacks, Roberts remains in the shadows. A firebrand candidate who wanted to challenge him from the right might have a chance. Likely names do not compare well, though. Roberts has big leads over specific GOP alternatives Public Policy Polling tested -- a 21 point edge against Todd Tiahrt, 31 over Tim Huelskamp, and 36 points over Kris Kobach.

Roberts can take solace in powerful allies, having the state GOP machinery behind him. The motive force that helped Roberts in 2008 and conservative candidates in 2012, David Kensinger, could serve as Roberts' most powerful ally in 2014. The support of Kensinger would likely deter the strongest of challengers who learned the lesson to not challenge the governor and his allies, keeping a vulnerable senator's seat safe.

Chapman Rackaway is an associate professor of political science at Fort Hays State University.