Here's a taste, but read the whole thing,
First, ...the reason the White House is digging in its heels despite really, really bad signals from the Hill is that it knows it instantly loses a ton of power if it loses this debate. Four years is a long time to be a lame duck.And as I, Krugman and Noam have argued before, these private accounts are a bad idea.
The second point follows from the first. Since the White House knows it has to come away with something or else risk extended lame-duckness, I suspect we'll eventually see every effort to forge a compromise. And the compromise I expect to see is add-on accounts--i.e., private investment accounts that supplement your Social Security check, not partially replace it--which even the AARP is on-record supporting.
Go read the whole piece.