The Senate shouldn't change its rules to undercut the filibuster, Sen. Ben Nelson (D-Neb.) said Wednesday.

Nelson told a local media outlet that he has reservations about efforts by his Democratic colleagues in the Senate to change rules surrounding the filibuster, a key procedural tactic used by Republicans to slow down or block pieces of legislation.

“The last thing we need to do is start changing rules, with 51 votes and simple majority, and make the Senate a smaller version of the House," Nelson told the Omaha World-Herald.

Nelson's comments would seem to clash with earlier reports that all of the Senate's returning Democrats had signed a letter to Majority Leader Harry Reid (D-Nev.) endorsing a change to filibuster rules. 

Still, Nelson has broken with his party on key votes several times over the last few years. He'll be one of the most-targeted incumbents by Republicans in 2012.

Under current rules, the Senate needs 60 votes to end debate on most items, a practice which has become more frequent with Republicans in the minority.

Democrats, led by Sens. Tom Udall (D-N.M.) and Jeff Merkley (D-Ore.), have pushed for changes to those rules. Changes under consideration could narrow the opportunities to wage a filibuster, or force senators to actually speak during one — among other options under consideration.

Democrats are expected to make an attempt to change the rules later in January, which they believe they can do with a simple majority under specific rules. 

Update, 9:48 p.m.: Jake Thompson, Nelson's communications director, clarified the senator's stance in a statement:

Senator Nelson is no fan of the filibuster as a one-size-fits-all tool to cause gridlock. At the same time, he isn’t willing to go along with just any idea so the Senate ends up working like the House. He isn’t suggesting the rules shouldn’t be changed to deal with the filibuster.  He’s saying that the rules shouldn’t be changed so that anything goes with a simple majority vote.