From Newsweek's Jonathan Alter:
For four and a half years, Bush has politicized 9/11. His political motto has been "The only thing we have to use is fear itself." He was at it again last week, claiming with zero evidence that congressional scrutiny of the illegal NSA wiretapping would "give the enemy a heads-up on what we're doing." The media and the Democrats have both been intimidated by this devastatingly effective political strategy. It won the 2002 and 2004 elections for the Republicans and will continue to be their game plan for this November.
At first glance, making the Democrats seem soft on "terrorist surveillance" looks like another winner for the GOP. For Democrats to explain that they don't oppose all eavesdropping but object to the way it was done is a two-step answer that's too complicated to fly. A better approach would be to argue that Bush's NSA program has been a failure because it has threatened civil liberties and violated the law without doing anything to catch Osama bin Laden. The NSA obviously hasn't been eavesdropping on the right suspects.