Once the Republicans go 24/7 (and they will once all 51 are on the floor, IMO, but not before), the Democrats will be stuck. No major media has come out in support of them. The daily papers are all editorializing against the Democrats (Hatch read some on the floor last week) and the broadcast TV media are ignoring the story for now in order to run cover for the Democrats.
Once McConnel and Bunning are back and the Republicans go 24/7, Hatch will read more and more of the editorials against the Democrats. Then they will turn the heat on the TV media to cover the story (I'll know that the Democrats are ready to cave when the Perky Katie Couric covers the story).
Going 24/7 (dubbed the nuclear option by some) will require a coordinated effort between the Republicans and the White House, because there will be pressure on both sides: the Republicans to move onto other business, and the Democrats to relent. The Democrats have the weaker argument, but they have nothing left to lose. The Republicans must realize that if they lose this then they lose the next two years as well.
Time is on the Republicans' side. They just need to withstand the initial onslought.
-PJ