Senator Tom Udall (D-NM) was on The Rachel Maddow Show to explain his proposal to reform the Senate's rules on the first day of the 112th Congress.
Now Senator Jeff Merkley (D-OR) is jumping in. Via Think Progress:
Sen. Jeff Merkley (D-OR) laid out a path to fundamentally change the way the filibuster works. Merkeley told [Thom] Hartmann to “mark this date on your calendar: January 5th. That’s the date we’re going to come in for the next Congress, and it’s on that date that a group of us is trying to pass a motion for the Senate to adopt new rules.” [...]
Merkeley writes that he would “require a specific number of Senators — I suggest five for the first 24 hours, 10 for the second 24 hours, and 20 thereafter — to be on the floor to sustain the filibuster. This would be required even during quorum calls. At any point, a member could call for a count of the senators on the floor who stand in opposition to the regular order, and if the count falls below the required level, the regular order prevails and a majority vote is held.”
Tom Harkin has expressed his frustrations about the filibuster previously. I wrote about it back in February in a post called "Restoration of majority rule": Tom Harkin, Jeanne Shaheen eye filibuster reform:
Harkin proposes a new procedural model: the first go-around, the minority could demand a 60-vote majority, as is the case now. But if 60 votes aren’t there to end debate, a week or so later, 57 votes could bring the bill to the floor for a vote. If 57 votes aren’t there, it drops again and again, and after a month or so, a bare majority could approve cloture.
Here is a more recent statement:
"...Get rid of the filibuster once and for all..." (starts at about 3:18)