I’ve been trying to follow the Iraq War supplemental spending machinations and it is really difficult to see where things are going. I think Greg Sargent has the basics right. We’re down to the endgame and it is a matter of who blinks first. The Democratic leadership is still looking at polling and they don’t like what they see.

Recent polls suggest that Dems haven’t done a good enough job explaining to the public that the Presidential veto — not Congress — is what’s to blame for the lack of troop funding. So a repeat of the veto scenario is thus seen as politically very risky, our staffer says.

There is no talk of sending the same bill back up for a second veto. The Dems have promised to produce something that will be signed by Memorial Day. They don’t want to fail in that promise.

“The storyline in the media would then be, `Dems fail to meet their own set deadlines, Dems in disarray,'” the staffer says. (Of course, sending the same bill back doesn’t appear to be under consideration by the leadership in any case.)

As a result, there have been no preparations through the media laying out an alternative storyline wherein the President is the failure. Thus, all signs point to a capitulation by the Democrats.

As Sargent notes, though, nothing is certain.

On the other hand, the Dem leadership insists it’s committed to not giving Bush a blank check, and it has consistently hung much tougher than anyone expected and has steadily defied expectations in the process. So anything, of course, can happen.

Look, the whole process thus far in some ways has been very good for liberals. There have been straight up-or-down votes on ending the war in both the House and Senate. Progressives have gradually strengthened their hands in Congress.

That’s all true, but caving in now will largely wipe out those gains and let the congressional Republicans off the hook.

“If this is what they go with, it begs the question, Why did we go through this whole exercise with the first supplemental and everything else?” our staffer asks. “What did we really accomplish?”

Worse, he says, aside from the fact that the benchmarks-with-no-accountability measure would be a substantive failure, it also contains a serious political pitfall. If the final compromise has (meaningless) benchmarks that the White House initially opposed, the possibility is that Republicans in Congress, by supporting such a measure, would be the ones perceived as having been the bridge of compromise between Congressional Dems and Bush.

“If the Republicans come across as brokering this deal, not only have we gained nothing, but they will have gained a lot,” he says. “The Republicans will be the ones perceived to have brought Bush back into line. This is certainly not a gift we want to give them.

Look at it this way: the Dems are certain to lose a lot if they cave, and it will all be to avoid a highly speculative risk based on reading polls quite selectively. The polls may show that the public doesn’t fully appreciate that Congress has already provided a spending bill, but they also show that the public strongly supports the Dems position on creating accountability and setting a timetable to bring the troops home. Bush has never been weaker or less credible.

Caving in now will split our caucus, give the opposing caucus new life, strengthen the President, and do nothing to end the war. I encourage our congressional leaders to reconsider their strategy. Don’t cave.