Editor’s Note: Stephen I. Vladeck is the A. Dalton Cross Professor in Law at the University of Texas School of Law, a CNN contributor and an expert on the role of the federal courts in the war on terrorism. The views expressed here are solely his. View more opinion at CNN.

CNN  — 

In an unexpected move on Monday night, the Justice Department notified the Fifth Circuit US Court of Appeals that it is supporting a complete invalidation of the Affordable Care Act (Obamacare). It now believes not only that three provisions of that statute are unconstitutional, but that, as a result, the entire law, including dozens of provisions having nothing to do with the offending sections, should be thrown out as well.

What is especially galling about the move is that it was apparently ordered by the White House over the objections of Attorney General William Barr, Health and Human Services Secretary Alex Azar, and White House Counsel Pat Cipollone. If Barr cares at all about the long-term institutional credibility of the Justice Department, he should resign in protest.

Stephen I. Vladeck

Throughout American history, the Justice Department has assumed an ethical and legal responsibility to defend the constitutionality of federal statutes so long as reasonable grounds exist for doing so. Even if the current President or attorney general finds a federal law distasteful or unwise, the government is still obliged to defend the validity of the law in court.

As then-Attorney General William French Smith wrote in 1981, “the Department appropriately refuses to defend an act of Congress only in the rare case when the statute either infringes on the constitutional power of the Executive or when prior precedent overwhelmingly indicates that the statute is invalid.”

Defending all statutes capable of reasonable defense shows proper respect to the legislative branch and is one of the most significant ways in which the Justice Department is more than just another arm for achieving the incumbent President’s partisan policy priorities.

It’s because of this obligation that heads turned last year when the Trump administration announced that it would not defend the constitutionality of some of the key provisions of Obamacare, including the individual mandate and the guarantee of coverage for pre-existing conditions, after Congress zeroed out the penalty for failure to comply with the mandate in its controversial 2017 tax bill. The Trump administration chose to support, rather than defend against, a challenge to those provisions by a group of states. But as troubling as that decision was at the time, what happened on Monday was much, much worse.

To make a long story short, the district court hearing the states’ lawsuit ruled last December not only that these provisions of the ACA were unconstitutional, but that, as a result, the entire statute – including provisions wholly unrelated to the contested sections – must be discarded. The Trump administration had argued in the district court that the rest of the statute (everything from the major expansion of Medicaid to the provision of funds for opioid and HIV programs) could still be applied despite the offending provisions, but Dallas federal district judge Reed O’Connor disagreed.

On Monday, the Justice Department signaled to the Fifth Circuit, which will soon hear the appeal from the district court’s ruling, that it now endorses the district court’s reasoning in its entirety – and that it agrees that the entire statute, and not just the putatively unconstitutional provisions, must be invalidated. According to widespread reports, this decision was made by senior White House advisers without taking to heart the concerns of White House staff, counsel, and top lawyers who did not believe the decision to be justified. Such a move is incredibly significant – and deeply alarming – for at least three independent reasons.

First, as unusual as it is for the government to change its litigating position from one administration to the next, it’s virtually unheard of for the government to so fundamentally change its position within the same administration. Presumably, there should be a truly compelling reason for such a change. Here, though, the legal argument the government is relying on – that the offending provisions render the entire law invalid – has been so thoroughly debunked by experts from across the political spectrum that it’s impossible to imagine what the legal justification for the change could be.

Second, part and parcel of the Justice Department’s obligation to defend the constitutionality of federal statutes is the obligation to defend as much of the statute as can reasonably be saved. Even if the Justice Department properly concluded that there is no reasonable basis for defending the provisions of the ACA that the district court invalidated (which is itself a deeply contested premise), defending the district court’s conclusion that the entire statute must therefore fall is a different matter altogether.

Third, all of this would be troubling enough if the Justice Department had insisted on such an unprecedented litigation shift, and if the decision was made collectively by senior policymakers and lawyers. That’s what happened in 2011, when the Obama administration controversially shifted position on the constitutionality of the Defense of Marriage Act only after Attorney General Eric Holder reached a legal conclusion about why that statute could no longer be defended (one the Supreme Court subsequently endorsed).

Here, in contrast, the change in litigating position to argue that the entire ACA must be thrown out was made solely by political advisers, and over the express objections of all of the key legal advisers, including the attorney general and the White House counsel. As opposed to changing positions because the Justice Department changed its view as to whether the law could be defended, the shift here was solely to serve the White House’s political agenda and nothing more.

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    There are any number of formal and informal legal doctrines that presume that the Justice Department acts in good faith when litigating on behalf of the federal government. The more that it looks like the government’s litigating position reflects nothing more than the political whims of the White House, the less credibility the Justice Department will have going forward in all litigation – not just in high-profile cases like the dispute over the ACA.

    No one would argue that the attorney general can overrule the President. But when the President demands that the Justice Department take an unreasonable litigating position for partisan political purposes, an attorney general who cares about the Justice Department’s long-term credibility can refuse and be fired (such as then-Acting Attorney General Sally Yates, who refused to defend the first iteration of President Trump’s travel ban), or he can – and should – resign.