Sen. Lamar Alexander (R-Tenn.) on Tuesday announced he will step down from his post as Senate Republican Conference chairman in January.
Alexander made the announcement in a letter sent to his Republican colleagues in the Senate.
Alexander's decision to step aside from GOP leadership comes as a surprise, as he had previously said he would run for the No. 2 position in the conference in 2013, when Arizona Sen. Jon Kyl, the Republican whip, retires.
Sen. John Cornyn (R-Texas), the chairman of the Senate GOP's campaign committee, has also said he will run for the whip position and could have an inside track on the job if the GOP recaptures the chamber in 2012.
The move also clears the way for Sen. John Thune (R-S.D.) to ascend the ranks. Thune announced Tuesday that he will run to succeed Alexander as chairman. A rising star in the party, he currently holds the No. 4 position in leadership as chairman of the Republican Policy Committee.
Alexander made clear in his letter that, although he's stepping down from his leadership position, he plans to run for reelection in 2014.
"I said to Tennesseans when I first ran for the Senate that I would serve with conservative principles and an independent attitude," Alexander said in the letter. "I will continue to serve in that same way. I am a very Republican Republican. I intend to be more, not less, in the thick of resolving serious issues. And I plan to run for re-election in 2014."
Alexander said leaving the post would "liberate" him and give him the chance to provide a different kind of leadership in the Senate.
"Stepping down from leadership will liberate me to spend more time working for results on the issues I care most about," Alexander continued. "I want to do more to make the Senate a more effective institution so that it can deal better with serious issues. There are different ways to provide leadership within the Senate. After nine years here, this is how I believe I can now make my greatest contribution. For these same reasons I do not plan to seek a leadership position in the next congress."
In his floor speech announcing his decision, Alexander said stepping down will let him be more aggressive on certain issues related to the Senate.
"I look forward to this. The Senate was designed to be the forum for confronting the most difficult issues producing the biggest disagreements. I don’t buy for one minute the notion that such policy disagreements produce an unhealthy lack of civility," Alexander said.
He continued, pushing back on the notion that the political climate in Congress is too heated.
"It would help to produce better results if we senators knew one another better across party lines. But to suggest that we should be more timid in debating the issues is to ignore American history and the purpose of the Senate. In fact, senators do our jobs with excessive civility," Alexander said.
Alexander, a former governor and secretary of Education, mounted unsuccessful bids for the White House in 1996 and 2000.
Speaking after Alexander finished his floor speech, Senate Minority Leader Mitch McConnell (R-Ky.) praised him and said repeatedly that "this is not a eulogy."
"Really, I think I have a great sense of relief that my friend is going to run again in 2014 and continue to make an extraordinary contribution to the senate and to America," McConnell said. "It's hard to think of anybody who's done more things well."
—This post was last updated at 12:00 p.m.