Let's start with a little background. After winning the Presidency and both houses of Congress, the Democrats went on a major spending spree. After years of complaining about the Bush deficits, they tripled it. The Tea Party formed largely as a response to this unprecedented spending and took back the House of Representatives.
In 2011, the government was about to hit the debt ceiling - the amount that it can borrow to cover its expenditures. While increases int he debt ceiling are usually non-controversial, this time the Republicans refused to raise it without cuts in spending. With a deadline coming quickly, the White House came up with a deal - in exchange for raising the debt ceiling high enough to get Obama past the election, he would support future cuts to be decided by a congressional super-committee. To be sure that the super committee did it's job, the deal also included the sequester. This is an across-the-board cut of with the deepest cuts being in the military. The idea was that Democrats would not want to see their favorite programs cut and Republicans would not want to see the military cut.
The super-committee failed. A December 31st deal on the Fiscal Cliff raised taxes on the wealthy and postponed the sequester for two months.
So where are we now?
The Republicans' position is simple - taxes have already been raised without any cuts. Now it is time for cuts. They are willing to discuss reapportioning the cuts but their constituencies will not support any new taxes.
The Democrats have their own position. Since Obama won the election, the Republicans should agree to anything the Democrats want. They will not approve any bill that does not include significant new revenue.
A lot of political calculation went into the Democrats' position. First, they really do believe that the election means that the Republicans should defer to them on all things, especially tax increases. They have been accused of moving the goalposts on this since the original deal was for cuts only and since taxes have already been raised without any spending cuts.
The Democrats have an eye on the next election and much of their strategy is the opening gambit for that. They hope that if they can force a tax increase then it will split the Republicans' coalition and allow the Democrats to retake the House. If that fails then they hope that they can blame the sequester on the Republicans. Obama began rewriting history during the third debate and have continued to insist that the sequester was the brainchild of the nasty Republicans. No less authority than Bob Woodward has taken issue with this account.
The Republicans have passed two proposals for replacing the cuts. The Democrats have rejected these but refused to make their own suggestions that don't include tax increases. Chance are they are reluctant to advance a cuts-only proposal because they know the Republicans would accept any reasonable offer.
Many Republicans have concluded that, as bad as the sequester is, it is the only deal that they will get that does not involve raising taxes.
The big danger for the Democrats would be for the sequester to take place and for the consequences to be less than predicted. Given the magnitude of the the disaster the President has described, the actuality is likely to be a dud.
That is the risk the Republicans are taking.