The point is to replace the uber-RINO with an acceptable Republican. To say he is the "best" we can get in RI is defeatist and untrue. And lastly, Chafee cannot be counted on to vote Republican even on said procedural matters. He did not even vote for President Bush last November.
I'm no fan of Lincoln Chafee, but he's 1000% better than Charles Schumer, Ted Kennedy or Robert Byrd, which is exactly the kind of politician that will likely replace him. If you want to get rid of RINO's, you should go after John McCain or others of his ilk that come from red states.