In particular, it's the filibuster rules, where currently it takes 60 votes to overcome a filibuster. Even worse just the "threat" of waging a filibuster is all it takes for any member to preclude any legislation, any vote on presidential appointments or any business from taking place until the threat is overcome and/or satisfied. Who knows how that is done as it's often done secretly so the public has no idea who is doing the obstructing.
As to the obstructing culprit it's usually a member of the minority party enabled by the minority party's leadership bringing what I refer to as the "tyranny of the minority".
Majority's don't rule, where it takes 60 votes to do anything, so much as the minority essentially dictating whatever is done in this "august" body.
The major fear of changing the rules by any current majority has been what happens when they become the minority; they'll lose their ability to exercise the filibuster.
Well that subterfuge won't wash any longer if Reid and the Democrats can do the right thing and reform this abomination and subversion of democracy.
Even then there's no chance of actually ending the filibuster. The latest reports on reform would require an actual "talking filibuster" that require Senators to talk continuously on the floor of the Senate to keep their obstructionism going or the far weaker idea of mandating 41 actual votes on the floor to uphold a filibuster.
The filibuster isn't in the Constitution. It's a bastard creation as the Constitution requires only "Each House may determine the Rules of its Proceedings". [ii]
In America, when it comes to anything of significance in getting something done or keeping the status quo, the basic rule of thumb is always "follow the money."
Reforming the Senate filibuster rules should be a no brainer. But if nothing is done in this regard you can bet moneyed influence has played its part in scuttling filibuster reform.
Any other verbal gymnastics given by Reid and the Democrats should filibuster reform not occur would be pure political posturing, obfuscation and dissembling.
[i] See "Senate Filibuster Reform Vote Delayed Until January 22", by Dave Lefcourt, OPEDNEWS January 4, 2013.
[ii] Article I, Section 5 of the Constitution reads, "Each House may determine the Rules of its Proceedings".