David French at National Review:
One thing that is abundantly clear from reading the full text of President Trump’s declaration of a national emergency on the southern border — he’s barely even deigning to explain why there is a particular crisis today, or why that crisis is so grave that it requires the military to combat it. At its heart it’s a contemptuous document. It’s the proclamation of a monarch, not an argument by a president. And it should fail in court.
...
Before today, legal writers were guessing at the statutes the president would use to justify defying the will of Congress and using the military to build his border wall. Now we know. In his declaration, he’s exclusively using 10 U.S.C. 2808 to reallocate up to $3.6 billion from Department of Defense construction projects — more than double the amount that Congress allocated for wall construction in its border compromise. (He intends to use other funds as well for wall construction, but those aren’t applicable to the emergency declaration.)
...
The intent is clear — to grant the military the power to build out military installations, and a “military installation” is a “base, camp, post, station, yard, center, or other activity under the jurisdiction of the Secretary of a military department or . . . without regard to the duration of operational control.” Each of the precisely described forms of installation represents facilities that support the troops. Under basic rules of statutory construction, the “other activity” must also fulfill that same purpose. As the Supreme Court held in Circuit City Stores v. Adams, when “general words follow specific words in a statutory enumeration, the general words are construed to embrace only objects similar in nature to those objects enumerated by the preceding specific words.”
A border wall, by contrast, is a civilian structure to be manned by civilian authorities to perform a civilian mission. The troops would not be creating a military fortification for military use. Not only is it not “military construction,” it’s also not “necessary” in order to support the use of the armed forces — unless one wants to make the fantastical argument that the wall somehow “protects” the troops who are building the wall. They are not defending the border from actual invasion as defined by the law of armed conflict or relevant American law. They are assisting in a law-enforcement mission that is mainly designed to prevent the commission of federal misdemeanors, not to stop an army that intends to take and hold American territory
At Lawfare Scott R. Anderson abd Margaret Taylor acknowledge that a president has discretion to call a national emergency, but:
Can § 284’s authorization to build a “fence” to “block drug smuggling corridors” really be used to build a wall across the entire southern border? Is the wall really a “military construction project” of the sort authorized by § 2808? Does the president’s declaration of national emergency really “require[] the use of the armed forces” as required by § 2808? The patchwork of legal authorities on which the Trump administration is relying exposes the administration to a wide array of these challenges. One possible outcome may be a partial victory and partial defeat, in which the Trump administration is able to rely on some authorities and associated funding but not others. Regardless, plaintiffs are likely to seek—and federal courts seem likely to grant—injunctions that stop the federal government from taking any irrevocable steps towards building the wall while these legal challenges are resolved. In this sense, the primary function of these challenges may be to buy time until Congress is able to impose new limitations on the use of these funds and authorities, or even until a new Congress or a president is elected in 2020 who no longer wishes to pursue this agenda.