The positive difference is that Lieberman understands the issues in the war on terror, including the battlefront in Iraq. Also, it's not a zero sum game. With Chaffee and Lieberman in office in the last Senate you had two liberals, one of whom understood the WOT. Now the really bad actor, Chaffee, is gone and Lieberman is moving towards goodness.
The trend is our friend.
Wolf Blitzer just told Feith that the IG report substantiated that there was no "operable" close relationship between Iraq and al-queda in the run up to 9/11.
Feith said that HE never said there was...and that Wolf SHOULD have known better.
I'm happy on Lieberman's stance on national security. I have serious doubts, however, he would make a change...unless he plans on retiring after his current term. It's unlikely his constituents would support him in 2012 if he changed parties.