Ken Salazar is perfecting it. He doesn't seem to realize he'll never please the reactionary [R]'s here in CO, but he can't pull the trigger on doing the things that will build his support among progressives and independents: standing up for the rule of law and competence in government.
I also remember Kerry on MTP prior to the election when Tim Russert asked him if he was liberal.
Kerry hemmed and hawed.
I don't have any answers right now, just complaints.