That's not all; as the linked clip demonstrates, President Obama appropriated his authority as a constitutional law professor to denounce President Bush's use of signing statements as unconstitutional.
So now, the question is: Was he wrong then, or is he acting against the Constitution now, in his post as Chief Executive (clarification: When he appended a signing statement to the defense bill)?
Don't get me wrong. This isn't the kind of issue that voters particularly care about -- but it's incredibly powerful as an illustration of Obama's complete cynicism. The headline from Politico says it all: "Left bloggers hail 'new Obama'" (for his extra-constitutional end run around the Senate). And that desperation to enhance the flagging enthusiasm among his core supporters, in the end, likewise is the motivation for the President to act in a way that he himself has characterized, offering an "expert" opinion, as unconstitutional.
Let's hope the RNC is readying the attack ads, using this and of all Obama's other failed promises, masterfully compiled by Jim Geraghty here. Many Americans took a chance on Obama in 2008, and it's important to give them a reason to withdraw that support without making them admit to themselves that they were in error.
In fact, they were hoodwinked. And no one can be blamed for that -- besides the President.