It’s becoming something of a progressive article of faith that the increasingly frantic demands by Republicans that the president put specific spending reductions on the table reflect the GOP’s own inability to articulate what they actually want–or at least what they will publicly admit they actually want.
I agree with that assessment, but something else a bit simpler is also going on: given the pressure being constantly placed on congressional Republicans to prove a mere election defeat didn’t reduce their passion for a conservative policy revolution, many, perhaps most, GOPers in Congress need an Obama proposal, or perhaps several Obama proposals, to reject. So they have at least as large a stake in Obama offering a “liberal” fiscal blueprint as do progressives fearing he’ll concede too much. There exists, of course, a sizable bloc of Republican members of Congress who will oppose any Obama proposal–or indeed any fiscal agreement–to the bitter end. This will probably, in fact, amount to a de facto majority of House Republicans if we are talking about a pre-January 1 “fiscal cliff” agreement, given the increasingly popular position that Republicans should “allow” Obama to “win” the tax debate (with a minimum of Republican votes) and thereby “own” higher taxes, keeping their own powder dry for an apocalyptic battle over spending in connection with the debt limit increase just on the horizon.
At that point, most Republicans will still feel the need to denounce one or more Obama proposals, with some determined to oppose them all on grounds that spending should be cut to make a debt limit increase unnecessary, or hitting the limit would have no economic consequences, or whatever. It’s the size of the various blocs of nay-sayers that will ultimately matter.
You can read a game-theory explanation of how this all works by John Patty. But it all revolves around the desperate need Republicans have to eternally cover their right flanks.