During the lame duck session, a continuing public dedication to bipartisanship might make sense because there may still be a few bills that he can pass with just a few Republican votes. And it's easier to get those votes if he's not out in the Rose Garden every day telling the world that Republicans are all obstructionist assholes.
But starting next year that won't be true anymore.
Republicans will control the House, and in the Senate it will take a significant chunk of the GOP caucus to get anything passed. Sweet talking Olympia Snowe will no longer even arguably be a viable strategy. Obama's only hope is to draw dramatic contrasts with Republican orthodoxy, call them out relentlessly on their obstructionism and corporate obeisance, and try to rally public opinion to his side. It might not work, but there's no better alternative.
My view is that this will only work if Obama outflanks the GOP on long-term debt-reduction. He needs to make it the signature reform of his last two years just as health insurance reform was the lodestar of his first two. And they are bookends - united by being tough, difficult questions which need addressing now by a president who can use his bully pulpit to insist on long-term debt reduction in the next two years. When he has more concrete plans for this than the GOP, the tea party heads will explode.