Some commentators have suggested that an Obama or Clinton presidency wouldn't be an utter disaster, given the ability of GOP senators to stymie statist legislation by voting "nay" on cloture motions. (A cloture motion is a motion to cut off debate, that is, to stop a procedural filibuster.)
But...there may be only 44 GOP senators in the next Congress (down from 49). In that event, it could be hard to round up 41 "nays," given the number of RINOs and half-baked conservatives on the GOP side of the aisle (e.g., Snowe and Collins of Maine, Specter of Pennsylvania, Coleman of Minnesota, Smith of Oregon). That will be especially true on critical issues where RINOs are notably soft (e.g., health care and defense).