“One of our main focuses is making people stand up and explain to the American people why they are filibustering,” said Senator Amy Klobuchar, the Minnesota Democrat who has been working with Mr. Udall to develop changes in the way the Senate operates.

She said she and others would prefer to work with Republicans to see if they can reach a bipartisan agreement but would not shy away from a floor fight.

Republicans, who forced more than 90 votes to cut off filibusters in the last two years, said they had little choice since Democrats on many occasions refused them any opportunity to propose changes to legislation. Mr. Alexander and others have warned Democrats to brace for a backlash should they act unilaterally.

In a speech prepared for a Tuesday appearance at the Heritage Foundation, Mr. Alexander reiterated his position that Democrats would be making a mistake. “Voters who turned out in November are going to be pretty disappointed when they learn the first thing Democrats want to do is cut off the right of the people they elected to make their voices heard on the floor of the U.S. Senate,” he said in his planned remarks.

The effort to rein in filibusters has attracted considerable support from Democratic activists who believe that Republicans have abused the rules to thwart the agenda of Mr. Obama and Congressional Democrats. Before adjourning in December, all Democratic senators who are returning for the 112th Congress signed a letter to Mr. Reid urging him “to take steps to bring these abuses of our rules to an end.”

Besides forcing senators to take the floor to defend their filibusters, Democrats also want to make it harder to stonewall the initial effort to bring a measure to the floor, a step known as the “motion to proceed.” They also want to ban the ability of senators to place an anonymous “hold” on a bill or nomination.

The tactic of defying the calendar and keeping the Senate in the same legislative day is not a new one. According to the Senate Historical Office, Senator Robert C. Byrd of West Virginia, then the majority leader, set the record of 162 days in 1980 when he kept the Senate in the same legislative day from Jan. 3 to June 12 over filibuster changes.