Creative Commons/Tony WebsterCreative Commons/Tony Webster

President Donald Trump claims he can use an "emergency" declaration to secure funding to use eminent domain to acquire land for his border wall, even without any additional congressional authorization. The validity of this claim is dubious at best. It is far from clear that emergency powers can be used to build the wall. Even if they can, it is questionable whether that would authorize the use of eminent domain to seize private property. And if the president succeeds in using an emergency declaration for such dubious purposes, it would set a precedent that conservative Republicans are likely to have reason to regret the next time a liberal Democrat occupies the White House.

In a recent New York Times op ed, Yale Law School Prof. Bruce Ackerman outlines some reasons why it would be illegal for Trump to use an emergency declaration to build the wall:

President Trump on Friday said that he was considering the declaration of a "national emergency" along the border with Mexico, which he apparently believes would allow him to divert funds from the military budget to pay for a wall, and to use military personnel to build it...

Begin with the basics. From the founding onward, the American constitutional tradition has profoundly opposed the president's use of the military to enforce domestic law. A key provision, rooted in an 1878 statute and added to the law in 1956, declares that whoever "willfully uses any part of the Army or the Air Force" to execute a law domestically "shall be fined under this title or imprisoned not more than two years" — except when "expressly authorized by the Constitution or Act of Congress...."

In response to the Hurricane Katrina disaster in New Orleans, Congress created an express exception to the rules, and authorized the military to play a backup role in "major public emergencies." But in 2008 Congress and President Bush repealed this sweeping exception. Is President Trump aware of this express repudiation of the power which he is threatening to invoke?

The statute books do contain a series of carefully crafted exceptions to the general rule. Most relevantly, Congress has granted the Coast Guard broad powers to enforce the law within the domestic waters of the United States. But there is no similar provision granting the other military services a comparable power to "search, seize and arrest" along the Mexican border.

Gerald Dickinson of the University of Pittsburgh (probably the leading academic expert on legal issues related to eminent domain and the wall) makes similar points here. On the other hand, Ackerman's Yale colleague John Fabian Witt argues that the issues are not as clear as the former suggests:

The truth is that the White House's emergency gambit reveals the full extent of Congress's dangerous delegation of emergency powers to the executive branch of the federal government. Elizabeth Goitein of the Brennan Center has collected a daunting list of statutes authorizing emergency powers, which is super helpful on this point. (Liza summarizes the statutes in a recent article at The Atlantic.) The upshot? Declaring a national emergency to build the president's ridiculous wall would be a national embarrassment. It ought to be unlawful, too. But whether declaring a national emergency to build a wall actually is unlawful under current circumstances turns out to be much closer question than it should be. The key statutory provisions are 10 U.S.C. 2808 (authorizing emergency reallocation of certain military construction funds) and 33 U.S.C. 2293 (authorizing emergency reallocation of certain civil works project funds).

A closer look at the two laws cited by Witt suggests it is far from evident that they authorize the diversion of funds to build a border wall. Section 2808 states that, if the president declares a "national emergency" that "requires the use of the armed forces," he can use military construction funds to "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." It is far from clear whether any supposed emergency caused by undocumented immigration really "requires the use of the armed forces" or that a wall would be "necessary to support such use" of them. Indeed, as Ackerman points out, federal law actually forbids the use of the armed forces for domestic law enforcement within the United States (and immigration enforcement qualifies as such). Section 2293 also only applies to a declared war or emergency that "requires or may require use of the Armed Forces." Even then, it only allows diversion of funds to build "authorized civil works, military construction, and civil defense projects that are essential to the national defense" (emphasis added). In this context, "authorized" likely means "authorized" by Congress, not just by the executive branch.

It is also worth noting that nothing remotely resembling a national security "emergency" is actually occurring at the southern border, and that a border wall would do virtually nothing to protect the US against any kind of terrorism or security risk. It may well not even do much to reduce undocumented immigration.

Thus, I would tentatively conclude that Trump cannot use these provisions to appropriate funds for the construction of a border wall - even if he does declare a "national emergency." However, courts often give presidents undue deference on national security and immigration issues, and that problem could recur here. I would be lying if I said I could confidently predict the outcome of a legal battle over this issue. I should also emphasize that I am far from being an expert on the full range of dubious emergency powers Congress has delegated to the president. So it's possible I am overlooking some other possible source of wall-building authority.

Even if Trump can otherwise use an emergency declaration to transfer funds to build a border wall, it does not follow that he can seize property through the use of eminent domain. As the Supreme Court has long held, the power to use eminent domain has to be "expressly authorized" under the law. Such authorization cannot simply be assumed or inferred. None of the emergency delegations of power for construction projects discussed above "expressly" authorize the use of eminent domain for purposes that are not otherwise authorized by Congress. If it is not clear whether eminent domain is authorized or not, courts are generally required to conclude that it isn't. Congress could, of course, solve that problem by giving Trump the authorization he needs. But the whole reason why Trump is considering using an emergency declaration is because Congress refuses to do that.

Finally, as Gerald Dickinson points out in an insightful Washington Post column, under the original meaning of the Constitution, it is likely that the federal government does not even have the power to use eminent domain within states (as opposed to on federal territories) in the first place. Dickinson relies on an important Yale Law Journal article on this subject by my Volokh Conspiracy co-blogger Will Baude (I discussed the implications of Will's work on this here). As Dickinson recognizes, it is highly unlikely that the Supreme Court will overturn longstanding precedent granting the federal government that power (even if wrongly). Still, it is ironic that conservative Republicans who claim to be originalists are willing to endorse what would be a massive constitutionally dubious use of eminent domain by the federal government - one of the largest federal takings in all of American history.

As Dickinson has emphasized in previous works on this subject (see here and here), the federal government owns less than one third of the land needed to build the wall. The rest would have to be seized from numerous private owners, Native American tribes, and state governments. That is likely to be both costly and time-consuming. It would also open the door to serious abuses of the kind we have seen in many previous eminent domain cases, including those undertaken for past, much smaller border barriers, in which the Department of Homeland Security compiled an awful record of violating procedural rules and undercompensating owners.

If Trump is able to overcome legal obstacles and use an emergency declaration to secure funds for the wall without congressional authorization and use eminent domain to seize the land he needs, conservatives are likely to have good reason to regret the precedent it would set. The same powers could easily be used by the next Democratic president for purposes that the right would hate.

Consider a scenario where Elizabeth Warren wins the presidency in 2020, but Republicans in Congress refuse to allocate funds she claims are necessary to combat climate change and institute the gigantic "Green New Deal" program many progressives advocate. President Warren could then declare climate change to be a "national emergency" and start reallocating various military and civilian funds to build all kinds of "green" construction projects. She could declare that climate change is a threat to national security, and use the Army Corps of Engineers and other military agencies to participate in the project.

Indeed, the claim that climate change is a menace to national security is at least as plausible as the claim that undocumented immigrants on the Mexican border are. The Obama Administration Department of Defense even published a report on the subject in 2014. And, of course, if President Warren decides she needs to seize some private property to carry out her plans, she could cite the Trump precedent to use eminent domain for that purpose. This is just one of many ways in which liberal Democrats could exploit the sorts of powers Trump claims here. It would not be difficult to imagine others.

Both Democrats and Republicans often fail to consider the long-term effects of presidential power-grabs they support when their party occupies the White House. Many conservatives seem intent on repeating that mistake here.