In legislation signed into law by President Obama last week, Congress has once again prohibited the expenditure of U.S. government funds to transfer detainees held at Guantanamo to the United States. 

Similar restrictions have been enacted every year since 2009.  But unlike in years past, President Obama reportedly is deciding whether to defy this ban. A number of his former and current advisers are urging him to do so, arguing that the prohibition unconstitutionally interferes with Obama’s authority as commander in chief of the armed forces. 

Acting on this advice, however, would be fraught with risk for both Obama and Congress.

Presidents typically don’t think twice about ignoring statutory prohibitions that they regard as unconstitutional. The issuance of presidential signing statements calling out alleged constitutional violations—a practice criticized by Obama as a candidate but favored by him as president—has long been used to put Congress on notice that such defiance is being contemplated. Typically the attitude of presidents in such cases is “sue me.”  

If Congress accepts that the president can disregard funding restrictions that he thinks interfere with his commander-in-chief authority with respect to the handling of detainees, he can equally well do so with regard to funding restrictions that interfere with his authority as commander-in-chief to send U.S. forces into combat whenever and wherever he wants.

In this case, however, the statutory prohibition is backed up by a criminal penalty.  When that happens, presidents cannot be so cavalier, because the legal risk shifts from being named as a defendant in a civil suit to being named a defendant in a criminal prosecution. 

The potential criminal penalty arises under the Anti-Deficiency Act, which makes it a felony punishable by up to two years imprisonment for any government official to expend funds in excess of amounts appropriated by Congress, or for a purpose for which no funds are available. The object of this law is to ensure that no official steals from the public treasury, either for his own benefit, or for the benefit of his favored projects. 

To be sure, there is within the Executive branch a legal theory called the “doctrine of unconstitutional conditions,” which holds that Congress can’t do through the appropriations power (such as conditions on the expenditure of appropriated funds) anything that it would be unconstitutional for Congress to do through a direct statutory mandate or prohibition. President Obama would have to rely on this doctrine to defy the ban on spending funds to transfer Guantanamo detainees.

But in practice, presidents rarely rely on this doctrine because of the risk of prosecution under the Anti-Deficiency Act. Even when presidents are confident that their attorney general won’t prosecute a particular violation of the Act, they have to consider the risk that the next president and attorney general may take a different view of the violation. This risk continues until the statute of limitations expires—five years after the date of the violation.

From Congress’s point of view, invocation of the doctrine of unconstitutional conditions in this case should also be deeply troubling.  The commander in chief authority is extraordinarily broad in the conception of most presidents. 

Most presidents claim, for example, that the War Powers Resolution unconstitutionally intrudes on their authority as commander-in-chief, and that in fact they have broad discretion to deploy U.S. armed forces into combat irrespective of the views of Congress.  And because the War Powers Resolution is a direct mandate imposed on the president rather than a criminally-enforceable restriction on the expenditure of funds, it has in practice become a dead letter.  Presidents are perfectly comfortable daring Congress to sue them over alleged violations.

Today when Congress really wants to end U.S. military involvement in a foreign conflict, it doesn’t rely on the War Powers Resolution, but rather on funding cutoffs backed up by the criminal penalties of the Anti-Deficiency Act.  Such cutoffs were adopted, for example, to finally end U.S. military involvement in South East Asia in the 1970s, and to keep the U.S. out of peacekeeping operations in the 1990s.  

If Congress accepts that the president can disregard funding restrictions that he thinks interfere with his commander-in-chief authority with respect to the handling of detainees, he can equally well do so with regard to funding restrictions that interfere with his authority as commander in chief to send U.S. forces into combat whenever and wherever he wants.  

Even proponents of closing Guantanamo therefore need to think through the implications of what Obama is considering.  Do they want to acquiesce in a legal theory that would negate the only real authority Congress has to end unpopular wars?

What’s truly remarkable is that Obama is considering this action with respect to detainees. Bush administration lawyers were widely condemned for writing legal opinions that allegedly condoned torture of detainees. Among other things, they were accused of assuring President Bush that his constitutional authority as commander-in-chief trumped the prohibition on torture and associated penalties set forth in the U.S. criminal code.  

This was considered such a lapse in legal judgment that their legal opinions were revoked and the Justice Department investigated them for professional misconduct.  After a five-year long review, Justice concluded in 2010 that Bush’s lawyers used “poor judgment” but were not guilty of professional misconduct. 

The legal reasoning that would permit the commander-in-chief to violate the ban on torturing detainees is no different from the reasoning that would permit him to expend funds to transfer detainees in violation of the Anti-Deficiency Act. 

It would be beyond ironic if, in his zeal to close Guantanamo, President Obama established that it was not poor judgment at all for Bush’s lawyers to suggest that Congress has no authority to regulate the president’s treatment of detainees.

Stephen Rademaker has spent more than two decades in senior national security positions in the government. His work has been published in the New York Times, the Wall Street Journal and the Washington Post, and he testifies frequently as an expert on legal and national security issues.