The argument is that Bush's political and public support has eroded, so therefore he will be forced to sign the bill instead of vetoing it?

I really mean no disrespect by asking this, but when have things like public opinion or political influence ever held any away over the choices this president makes?

The veto is already a foregone conclusion to many Republicans (as per this story).

The tide has turned against Bush, that is certain enough. Even Novakula is saying he's never seen an American president so isolated from his own party and his own members of Congress. But this argument isn't enough to convince me that Bush won't do what he does best -- ignore everything and everybody and stick to the status quo.