If you want to know how Joe Lieberman undermines his former party on national security issues, just look at his response to the London terror arrests.

Democratic leaders reacted to the foiled plot by highlighting the importance of working with allies and the unwillingness of the Bush Administration to implement the 9/11 Commission’s recommendations on airport security.

Lieberman used the occasion to blast Ned Lamont’s position on the Iraq war.

“If we just pick up like Ned Lamont wants us to do, get out by a date certain, it will be taken as a tremendous victory by the same people who wanted to blow up these planes in this plot hatched in England,” Lieberman said at a campaign stop for his lagging Independent bid. “It will strengthen them and they will strike again.”

Lamont rightfully noted that Lieberman’s attack “sounds an awful lot like Vice President Cheney’s comment on Wednesday. Both of them believe our invasion of Iraq has a lot to do with 9/11. That’s a false premise.”

Yesterday, Cheney said a Lieberman loss would embolden Al-Qaeda.

Does anyone really believe that Islamic terrorists, strengthened by the war in Iraq and Israel’s assault on Lebanon, are following a Senate race in Connecticut?

Do Republicans currently have a more useful ally than Lieberman?

Perhaps that’s why Karl Rove’s calling him and Ken Mehlmen’s refusing to endorse the GOP nominee. Because right now Lieberman’s the only credibility Republicans have left.