The Democrat-controlled Senate is planning on changing the rules for a filibuster. The White House has given its support.
For the past four years (minus a few months when the Democrats controlled 60 seats), the Republicans have used the filibuster and the threat of a filibuster to block legislation they strongly disapprove of. Since it takes nearly all of the Republicans, united, to wage a filibuster, this says a lot about the strength of their convictions.
The Democrats and the White House hate this. They feel that a simple majority should be all they need to pass their agenda and that the Republicans are abusing the filibuster.
The Republicans counter that Majority-leader Reid has abused his authority by refusing to allow Republicans to make a single amendment to important legislation.
Regardless, the Democrats will regret it if they change the rules. One of the iron laws of American politics is that no party can keep control forever. The way that the Democrats treat the Republicans today sets the tone for how they will be treated when the Republicans are in the majority. This could happen in 2014 when memories of the rule change will still be fresh.
There is a very good chance that the Republicans will take the Senate in 2014. Typically the party in the White House loses seats in this off-year election. There are two reasons for this, both relating to the President. This class of Senators was elected along with Obama in 2008. They will not have the benefit of Obama's coat-tails in this election. Further, by a President's 6th year, people are getting tired of him which helps the opposition. Reagan and Bush (43) both lost the Senate in their 6th year and the Republicans solidified their gains in Clinton's 6th year. All three presidents saw a drop-off in their popularity after their reelection.
Considering this, the Democrats should be leaning over backwards to be nice to the Republicans in the hope that they will reciprocate.