This piece was originally published on Just Security, an online forum for analysis of U.S. national security law and policy.

As the shutdown stretches on, the Trump administration is beginning to realize the severity of its consequences for millions of Americans and is desperately searching for a way out. While President Donald Trump did not declare a national emergency during his speech on Tuesday night and subsequently direct the military to build a border wall, the plan remains on the table. Axios on Wednesday cited an administration official as describing an emergency declaration as “the most likely ultimate option.”

This plan is not only outlandish—it’s also illegal. Commentators have noted that the military is prohibited from enforcing domestic law without express congressional authorization, and there are specific prohibitions that would apply directly to efforts to enforce immigration law. In addition to those concerns, there’s an even more basic one: The Defense Department lacks funding to build a border wall, and Trump’s claims of emergency authority do not change that.

There are at least three significant legal issues with Trump’s plan that stand in the way of securing funds for the military to build the wall. First, there is no emergency allowing for him to utilize the military in this manner. Second, the relevant emergency construction authority does not allow him to build a border wall, because the statute requires that the construction be needed to support the use of armed forces, but in this case, it would be the other way around. Third, the legality of seizing vast swaths of private, state, and tribal land to build a wall along the entire border is highly suspect at best.

In short, even if the president declares a national emergency, he cannot simply use the military to build a wall.

The president wants to use emergency powers to build the wall because Congress has not provided funding for it, meaning that any attempt by the Trump administration to do so would result in serious legal consequences. The Constitution requires that “No Money shall be drawn from the Treasury, but in Consequence of Appropriations made by Law.” This requirement is reaffirmed in the Anti-Deficiency Act, which states that government employees may not “make or authorize an expenditure or obligation exceeding an amount available in an appropriation or fund for the expenditure or obligation.” Any action by an executive branch agency necessarily requires funding, at the very least the salary paid to the individual carrying that action out.

When a government employee violates the ADA, the head of the agency is required to submit a report to the president and Congress detailing the violation and the actions taken. The ADA specifies that individuals who violate the law are subject to administrative discipline, including “suspension from duty without pay or removal from office.” For knowing and willful violations, there are criminal penalties, including up to two years in prison.

In an attempt to sidestep the lack of funding, Trump has proposed invoking emergency authority. Specifically, he reportedly wants to exercise emergency military construction authority pursuant to 10 U.S.C. Sec. 2808, which states that:

In the event of a declaration of war or the declaration by the President of a national emergency in accordance with the National Emergencies Act (50 U.S.C. 1601 et seq.) that requires use of the armed forces, the Secretary of Defense, without regard to any other provision of law, may undertake military construction projects, and may authorize the Secretaries of the military departments to undertake military construction projects, not otherwise authorized by law that are necessary to support such use of the armed forces. Such projects may be undertaken only within the total amount of funds that have been appropriated for military construction, including funds appropriated for family housing, that have not been obligated.

The National Emergencies Act sets forth the procedures for declaring a national emergency and for fast-track congressional review of that determination. (The law was passed in the wake of Nixon’s abuse of emergency authorities.) The authority is broad, with no specific definition as to what constitutes a national emergency. However, the declaration of a national emergency to justify emergency military construction is rare; the only recent instance in which a president invoked the provision domestically was after the terrorist attacks on the World Trade Center and Pentagon on Sept. 11, 2001, to do work on “military installations storing sensitive materials or demilitarized chemical weapons.”

While the National Emergencies Act provides broad authority to declare a national emergency, simply saying he thinks something is a national emergency does not provide Trump with the authority to build a wall. In order to use emergency military construction authority, there must in fact exist a national emergency “that requires use of the armed forces.” In other words, beyond declaring simply that a national emergency exists, the executive branch must be able to show that the emergency at issue necessitates use of the armed forces.

There’s no evidence that any such emergency exists with respect to our border with Mexico. Border crossings are quite low by historical standards. And while the Trump administration has falsely argued that a border wall is necessary to combat terrorism, its own data shows there is “no credible evidence” of terrorists crossing the Mexican border. Instead, there has been an increase in families with children escaping violence in Central America and seeking asylum in the United States. There is no reasonable argument that families and children seeking asylum constitute an emergency that demands a military response.

The proposal to use a sham emergency lacking in factual basis to convert the military into Trump’s personal construction company is not only illegal—it also raises serious practical concerns.

And while the administration has recently seemed to suggest that drug smuggling could be the basis for an emergency declaration, such a notion is not supported by the administration’s own Drug Enforcement Agency. According to the 2018 National Drug Threat Assessment, only a small portion of the heroin and fentanyl that comes into the country is smuggled between ports of entry where the wall would be built. Far more comes through the ports themselves.

But even if the Trump administration were able to argue for some type of emergency, or a court declined to closely review the executive branch’s judgment on this matter, it would also have to show that military construction was “necessary to support such use of the armed forces.” But as Trump has made abundantly clear, the construction of a wall is not to support the use of the armed forces; it’s the purpose of employing the military in the first place.

This is no small distinction. Congress provided emergency construction authority to allow for the Defense Department to begin military construction projects quickly to support emergency efforts. The touchstone is that there is an actual need for the military to act, and in the process of taking that action, the DOD may need to engage in construction without going through the detailed process normally undertaken prior to military construction. President Trump’s proposal turns this rationale on its head. Under his reported plan, the DOD essentially would be turned into Trump’s personal construction company, stepping in where the executive branch otherwise lacks authority to build.

Finally, any border wall could only be built on property under the jurisdiction of the DOD. Section 2808 only allows the DOD to “undertake military construction projects.” Section 2801(a) specifies that “ ‘military construction’ as used in this chapter or any other provision of law includes any construction, development, conversion, or extension of any kind carried out with respect to a military installation,” and Section 2801(c)(4) states that “the term ‘military installation’ means a base, camp, post, station, yard, center, or other activity under the jurisdiction of the Secretary of a military department.”

Federal lands make up less than one-third of the 2,000-mile southern border, and military bases are a small percentage of that. (This is assuming that the DOD could even claim jurisdiction over all federal land for these purposes, which is not a given.) Thus, if Trump intends to utilize the military to build a border wall, it would require seizing significant amounts of private, state, and tribal land along the border. Trump has explicitly discussed this option, saying he could use “the military version of eminent domain” to build his wall. However, absent congressional authorization, it is highly dubious at best that the president can simply seize the land. (See Youngstown v. Sawyer.)

Some legal commentators have suggested that rather than Section 2808, Trump might attempt to use authority under 33 U.S.C. 2293, which provides for reallocating funds for civil works during national emergencies. Similar to Section 2808, this provision applies to any national emergency that “requires or may require use of the Armed Forces,” meaning it would raise the same legal issues there. But even more importantly, this provision does not provide any new authority for the military to engage in construction projects. It’s a reprogramming authority, meaning that it allows for the DOD to reallocate funding between projects but not undertake new, unauthorized projects. The provision makes this clear, saying that the funding can only be utilized for “authorized civil works, military construction, and civil defense projects that are essential to the national defense” (emphasis added). It provides no new authority for the DOD to build a border wall.

The proposal to use a sham emergency lacking in factual basis to convert the military into Trump’s personal construction company is not only illegal—it also raises serious practical concerns. Any funding for emergency projects must be taken from existing funding for military construction, meaning that Trump will have to divert money from projects the military has determined are needed in order to pay for his border wall. That will not sit well with DOD officials, and it will also raise serious concerns among members of Congress when legitimate military construction projects in their districts are delayed or canceled.

In addition, the proposal would likely face significant opposition from the officials asked to carry it out. As with any action by the administration that involves use of taxpayer funds, there would be career officials throughout the government who would have to sign off on the use of funding and carry out the plan itself. Given the administrative and legal penalties associated with violating the ADA, they would likely have serious concerns about exposing themselves to those risks. Even if the Trump administration would look the other way, there would be significant congressional oversight. (And while the imposition of criminal consequences is admittedly unlikely in this context, the statute of limitations for criminal penalties would extend beyond Trump’s first term.)

But beyond all of these specific concerns, a broader issue is raised by this contemplated action. It is not only illegal and impractical, but wholly at odds with our constitutional structure and values. Trump’s proposal is the type of unilateral action one would expect to find in an authoritarian regime. The national emergency is not at our southern border. It sits in the White House.

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