President Donald Trump issued a memorandum [text] on Wednesday authorizing the National Guard [official website] to deploy the US southern border for additional security support.

Trump described the order as necessary to respond to a “crisis” that is “fundamentally incompatible with the safety, security, and sovereignty of the American people.”

The combination of illegal drugs, dangerous gang activity, and extensive illegal immigration not only threatens our safety but also undermines the rule of law. Our American way of life hinges on our ability as a Nation to adequately and effectively enforce our laws and protect our borders. A key and undeniable attribute of a sovereign nation is the ability to control who and what enters its territory.

Trump thus ordered the Secretary of Defense to “support the Department of Homeland Security in securing the southern border” including by “request[ing] use of National Guard personnel to assist in fulfilling this mission” under 18 U.S.C. § 502 [text].

In securing the border, the Secretary of Homeland Security and Secretary of Defense are to implement proper training and instruction to all military personnel. They are also directed to produce a report in 30 days “detailing their findings and an action plan, including specific recommendations as to any other executive authorities that should be invoked to defend the border and security of the United States.”

In support of the directive, the memorandum recited the president’s constitutional and statutory authority to issue the order and also noted that previous presidents who issued similar orders, including former presidents Barack Obama and George W. Bush.