The Repubs can block anything they want to in both the House and Senate... They also own the Supreme Court...
Where exactly is all of this Democratic power and might???
The only reason that the Repubs are going to go back on their Grover Norquist pledge is because they want to keep the power they have... If they "stand in the door way and bloke up the halls" this time then they know they will loose their majority in the House in 2014 and may very well give the Dems the "super majority" of 60 in the Senate that is required to over-ride their filibusters...