Updated: 12:21 p.m.

North Dakota Sen. Kent Conrad had been considering retiring for months before announcing his final decision Tuesday.

Sources close to the Democrat told Roll Call Conrad made a final decision over the holidays and that it was for personal reasons, not political. After 26 years in the Senate by the end of his current term, the Budget Committee chairman will be ready for new challenges, the sources said.

Roll Call Politics had rated his re-election as Leans Democratic. However, National Republican Senatorial Committee Chairman John Cornyn (Texas) had listed it among the top GOP pickup opportunities in 2012. Also, Conrad was already being hit with negative radio ads in the state by conservative nonprofit American Future Fund.

“In the wake of Senator [John] Hoeven’s overwhelming victory last year, Senate Republicans fully expected North Dakota to be a major battleground in 2012, but Senator Conrad’s retirement dramatically reshapes this race in the Republicans’ favor,” NRSC spokesman Brian Walsh said in a statement.

In a letter announcing his retirement, the Budget Committee chairman wrote that with the country facing $14 trillion in debt, “It is more important I spend my time and energy trying to solve these problems than to be distracted by a campaign for re-election.”

Conrad ran radio ads this month to defend the Senator against negative ads from the AFF. Because of that, the announcement came as somewhat of a surprise for Democrats.

But the early decision gives the party plenty of time to find a top-tier candidate to run in his place. Former Rep. Earl Pomeroy’s name has already been floated as a potential candidate, though Pomeroy and former Chief of Staff Bob Siggins recently joined Alston & Bird to work on the firm’s health care team.

“There are a number of potential Democratic candidates who could make this race competitive while we expect to see a contentious primary battle on the Republican side,” Democratic Senatorial Campaign Committee Chairwoman Patty Murray (Wash.) said in a statement. “North Dakotans have a long history of electing moderate Democrats to the Senate, and we believe they will have an opportunity to keep up that tradition next November.”

Meanwhile, at least one Republican had already taken a step toward running, and many more are expected to jump in with Conrad retiring. Roll Call reported last week that state Public Service Commissioner Brian Kalk set up a Senate exploratory committee.

Kalk told Roll Call on Tuesday that he doesn’t think his announcement had anything to do with Conrad’s decision to retire. Kalk said though the Senator’s announcement doesn’t change his own plans, it may affect which other Republicans decide to get in the race.
 
“I think you’ll see lots and lots of Republicans jumping into this race, and hey, God bless America, that’s what it’s all about,” he said.
 
Kalk said he found out about the Senator’s retirement in a text from his college-age daughter on Tuesday morning.
 
Other Republicans being mentioned as potential candidates include Tax Commissioner Cory Fong, Attorney General Wayne Stenehjem, Lt. Gov. Drew Wrigley and freshman Rep. Rick Berg.