In what can only be described as an escalating war between Sen. Jim Bunning and his own party’s leadership, the Kentucky Republican threatened to sue the GOP’s campaign arm if it recruits someone to run against him in a primary next year.

Bunning’s comments come a day after National Republican Senatorial Committee Chairman John Cornyn (Texas) seemed to give his most definitive statement yet that the committee is supportive of Bunning, who has insisted he is running for re-election in 2010.

Cornyn told Capitol Briefing, a Washington Post blog, the NRSC is behind Bunning if he’s running for re-election and that it would back the Senator if he were to get a primary challenge.

“My position is that this is Sen. Bunning’s decision to make, and as long as he says he is running, I will be supportive of him,” Cornyn said.

But on a conference call with Kentucky reporters, Bunning vented when he was asked if he was satisfied with the NRSC chief’s statement.

“I don’t believe anything John Cornyn says. I’ve had miscommunications with John Cornyn from, I guess, the first week of this current session of the Senate,” Bunning said, according to the Louisville Courier-Journal. “He either doesn’t understand English or he doesn’t understand direct: ‘I’m going to run,’ which I said to him in the cloakroom of our chamber.”

Bunning continued by saying that if the NRSC were involved in recruiting a candidate to run against him in a primary he would sue the committee for violating its bylaws.

“Support of incumbents is the only reason for [the NRSC’s] existence,” Bunning said. “So if they recruited someone and supported them in a primary against me, I would be able to sue them because they’re not following their bylaws.”

Bunning’s furor comes after Kentucky state Senate President David Williams (R) met last week with NRSC officials about a 2010 Senate bid. The meeting has been described as a courtesy visit, and whether Williams would challenge Bunning in a primary or only run if Bunning steps aside remains to be seen.

Republican insiders in Washington, D.C., and in Kentucky have become increasingly concerned about Bunning’s viability as a candidate and their ability to hold the seat if he is the nominee. Bunning has repeatedly asserted that he’s running for another term, even as GOP leaders such as Senate Minority Leader Mitch McConnell (R-Ky.) and Cornyn have continued to signal that Bunning’s decision may not be final.

Williams is a close friend and ally of McConnell, and according to KyPolitics.org, a blog that covers Bluegrass State politics, the meeting last week was arranged with the knowledge of high-level McConnell staffers.