Illinois Congressman John Shimkus (R-IL) could be facing a challenger in the 2016 Republican primary, from a currently serving state Senator.

State Senator Kyle McCarter (R-Lebanon) appears to be preparing a run to unseat Shimkus, who has been Illinois’ southernmost Congressman since 1997.

Reports indicate McCarter made several calls over the weekend to downstate Republican leaders, informing them of his intentions to challenge Shimkus in 2016.

Insiders say Shimkus staffers, along with Gov. Bruce Rauner staffers have unsuccessfully tried to dissuade McCarter from his plans.

During Saturday’s Little Egypt Festival Parade, McCarter revealed a new campaign logo, noticeably missing the name of the office he plans to seek.

One GOP source says McCarter may go so far as to announce his candidacy in Collinsville, Shimkus’ hometown, even though only a portion of the city is in the 15th Congressional District.

Election reports show Shimkus had $1.2 million in his campaign war chest on June 30, but is not unbeatable in the primary, according to local sources. At the same time, GOP insiders believer McCarter would need significant help from outside anti-establishment groups to give Shimkus a serious challenge.

Shimkus, who was first elected in 1996, vowed to limit himself to only six terms in office, but subsequently backed off that promise, saying he made a mistake making such a vow. He is now seeking his 11th term in Congress.