Don’t hold your breath. He (like Al Gore) has a long and tiresome history of talking liberal and progressive but somehow being absent when it’s crunch time.
Or, in this case, in making progressive noises when it’s too late to make a difference. Had he backed a filibuster a month ago loudly and strongly, well, then he would have meant it. But to back it just before the vote when it doesn’t look like they have the votes anyway, is just empty posturing meant to shore up his liberal flank.
I hope I’m wrong.