As a strong defender of executive power (when properly exercised) and executive privilege (when properly invoked), I am concerned when claims of executive power or privilege are abused for any reason – especially if they are invoked to shield potential wrongdoing. In addition to shielding the wrongdoing, it jeopardizes the very executive power that the president is entrusted with when Congress and the courts react – as they did in the post-Watergate era – to the abuse of power.

The House Committee on Oversight and Government Reform is rightfully investigating the Fast and Furious debacle, in which the administration allowed thousands of guns to flow across the Mexican border, resulting in the death of one U.S. border patrol agent and at least 200 Mexican citizens, according to the Mexican attorney general. The most glaring violation of executive power in that investigation before now was the refusal of the Department of Justice (DOJ) to turn over 1,300 pages of documents subpoenaed by the committee without even an assertion of executive privilege. Attorney General Eric Holder simply refused on his own initiative in a blatant act of stonewalling.

As Holder surely knew all these past months, there is no privilege that exists between Congress and the executive branch to withhold documents except the constitutional executive privilege, which is based on the separation of powers. For example, the attorney-client privilege does not exist between Congress and the executive branch because they have the same client – the American people. Holder also knew that executive privilege does not attach to documents automatically. It can be asserted only by the president or with his direct approval. It can be waived; indeed it should be waived in many or most instances when Congress needs the information for its legislative functions. So the slated House committee vote to hold Holder in contempt on Wednesday was unfortunately necessary to get him to at least reconsider his lawless course of stonewalling.

In a desperate attempt to prevent the contempt vote in the last few hours, Holder asked President Obama to invoke executive privilege to shield these 1,300 pages of documents from Congress, and the president agreed to do so. Yet that is not the end of the story. Even if properly involved, the Supreme Court has made clear that executive privilege is not absolute. DOJ must provide an explanation why all those documents fit one of the recognized categories of executive privilege. It is questionable whether they all are legitimately subject to executive privilege, for several reasons.

First, the Supreme Court in United States v. Nixon (1974) held that executive privilege cannot be invoked at all if the purpose is to shield wrongdoing. The courts held that Nixon's purported invocation of executive privilege was illegitimate, in part, for that reason. There is reason to suspect that this might be the case in the Fast and Furious cover-up and stonewalling effort. Congress needs to get to the bottom of that question to prevent an illegal invocation of executive privilege and further abuses of power. That will require an index of the withheld documents and an explanation of why each of them is covered by executive privilege – and more.

Second, even the "deliberative process" species of executive privilege, which is reasonably broad, does not shield the ultimate decisions from congressional inquiry. Congress is entitled to at least some documents and other information that indicate who the ultimate decision maker was for this disastrous program and why these decisions were made. That information is among the most important documents that are being withheld.

Third, the Supreme Court in the Nixon case also held that even a proper invocation must yield to other branches' need for information in some cases. So even a proper invocation of executive privilege regarding particular documents is not final.

And lastly, the president is required when invoking executive privilege to try to accommodate the other branches' legitimate information needs in some other way. For example, it does not harm executive power for the president to selectively waive executive privilege in most instances, even if it hurts him politically by exposing a terrible policy failure or wrongdoing among his staff. The history of executive-congressional relations is filled with accommodations and waivers of privilege. In contrast to voluntary waivers of privilege, Watergate demonstrates that wrongful invocations of privilege can seriously damage the office of the presidency when Congress and the courts impose new constraints on the president's discretion or power (some rightful and some not).

But there is at least one helpful development in Holder's request that the president invoke executive privilege to shield these documents: The president now owns the consequences of further stonewalling. There is no ongoing DOJ prosecution or investigation to protect. There is no obvious reason why the president can't waive even what legitimately privileged documents there are (which is probably far fewer than the 1,300 pages being withheld).

The American people will now clearly understand that it is President Obama who doesn't want them to know who is to blame for the Fast and Furious scandal – and whether his administration has done anything to prevent it from happening again.