Asking Republicans to be part of a televised forum on health care reform is a clever move: put up or shut up. Nonetheless, I'd guess it probably fails. Republicans are saying what you'd expect them to: we won't engage in sham negotiations. If you want us to come to the table, shelve this monstrous and unpopular plan and let's start over.
Democrats should recognize the tactic: they invented it. And used it successfully against Social Security reform in 2005. Sure, they wanted to do Social Security reform, they said. All Republicans had to do to bring them to the table was get rid of the central point of the reform: the private accounts. Astonishingly enough, they did not suffer at the polls, even though the president tried to stir up public discontent with their "obstructionism". The problem is, the public doesn't get mad at you for obstructing things the public doesn't like.