It's the forum he looks best in. He'll have the floor to himself, and everyone in Congress who wants to talk about health care will have to respond to what he says. There's a risk, obviously; he looks weak if he pulls the plug on health care reform on national television, and will end up looking impotent if he takes a strong stand for it and can't get his own party to go along.
The upside is that if he takes a strong stand for a health care reform bill -- defining the provisions of that bill with some specificity -- and the Senate Republicans block it, Republicans can be blamed every time health care costs go up during the next two-plus years. Obama keeps his base together by uniting them around the one thing all strong Democratic voters agree on, dislike of the Republican leadership.
And you never know whether something will turn up. As I've told you before, it may be a foregone conclusion that every Republican in the Senate will vote against any health care reform bill, but voting to prevent debate and a vote on passage is a level of obstruction comparable to that deployed by southern Democrats against civil rights legislation 40 years ago. There are probably Republicans in the Senate who could be made uncomfortable about that -- older Senators, mostly, beyond the reach of the permanent campaign machinery that sets the GOP party line these days. All they need to do is not prevent a vote on health care reform, and Obama's major domestic legislative priority is through.
Maybe this doesn't work. Maybe nothing works. All I'm saying that in Obama's position you try everything that might work, and you don't lose anything important by waiting until you have the public stage all to yourself to make your stand.
I'm forced to concede this may be possible if only because everything I've seen till this point has ranged from inexplicable to insane.