If new President Obama disagrees with old President Bush about whether Rove should assert executive privilege before Congress, who wins? Jack Balkin argues that the claim of executive privilege is weakened if Obama doesn't get behind it:
Thus, if the sitting President does not support the claim of executive privilege, the claim is greatly reduced in strength, because, as the Supreme Court noted, "it must be presumed that the incumbent President is vitally concerned with and in the best position to assess the present and future needs of the Executive Branch, and to support invocation of the privilege accordingly." The Court's reasoning is that the incumbent President recognizes that someday his aides may be called to testify after he leaves office.
So what will Obama do? Another good question. Balkan suggests that any president might have an incentive to invoke the privilege for a past president's aides to avoid setting a precedent that could allow the president's current aides to be investigated during the next administration. That reasoning assumes that a future Republican president would have any qualms about allowing Congress to investigate a Democratic president's aides. Republicans tend to be more concerned about damaging Democrats than they are about abstract principles.
Daphne Eviatar, quoted in this piece, notes that Obama, before becoming president, criticized the assertion that presidential advisors have "absolute immunity" to refuse to appear before Congress, but wonders whether his opinion will change now that he's sitting in the Oval Office.
After all, the executive privilege would now protect him and his cabinet, too.
Neither Obama nor any other president is likely to renounce his or her power to invoke executive privilege. But whether to invoke it in a particular case is a different question. Obama would not damage his (or any future president's) ability to invoke executive privilege in an appropriate circumstance by deciding not to use it to shield Karl Rove from testifying about his communications with the Justice Department about the Siegelman prosecution or the U.S. Attorney firings. It would be hugely disappointing if Obama were to obstruct a congressional investigation into those issues by directing Rove to invoke executive privilege.
It is more likely (as some of the linked sources note) that Rove will turn to the courts for help as he continues to stall. If he fails to win judicial support for his belief that President Bush's invocation of executive privilege trumps President Obama's decision not to invoke it, Congress could issue a contempt citation (a solution advocated by Rep. Jerrold Nadler). The Justice Department under Obama, unlike the Department under Bush, would presumably take the contempt citation before a grand jury and seek Rove's punishment. If it did not, that decision too would be hugely disappointing.
Whether any of this will happen, or whether some compromise will be reached (perhaps limiting the scope of Rove's testimony), we might learn in the coming weeks ... or months ... or years. All we know now is that Rove won't testify on Monday.