"The only reason we won't block [the Democratic bill] today is that we know it doesn't pass constitutional muster and won't become law," he said on the Senate floor. McConnell is referring to the Constitution's origination clause, which stipulates that revenue raising bills must have their first reading in the House -- not the Senate. The Democrats bill has what's known as a "blue slip problem."
But Senate Dems say they already anticipated that problem and have a way around it.
Senate Majority Leader Harry Reid can accept McConnell's offer to hold the tax vote at a 50-vote threshold Wednesday (suggesting again that Reid has his members lined up to pass it), but insist on holding the vote under an agreement with McConnell that would resolve the blue slip problem. Specifically, when House Republicans pass their bill at the end of the month to extend all the Bush tax cuts, it would automatically be amended by the Senate with whichever bill that passes today, and sent back to the House.
If the Democrats' bill passes -- as Reid is signaling it would -- the issue gets automatically kicked back to House, putting Speaker John Boehner on the hook for taking middle income tax cuts hostage in order to preserve tax cuts for the rich.
That's an agreement McConnell would be hard pressed to accept. But by rejecting it, he'd be preserving one of the Democrats' most potent lines of attack: that Republicans would rather let everyone's taxes go up than see tax cuts for the wealthiest two percent of earners in the country go up even a small amount.