President Donald Trump has ordered the U.S. military to take control of a strip of land near the U.S.-Mexico border. 

Fox News reports that Trump gave the order on Friday.

The White House released a memorandum on the situation, which can be read in its entirety here. It is called "Military mission for sealing the southern border of the United States and repelling invasions."

The title accurately sums up what Trump's intentions are here.

It's happening

During his campaign, Trump made it clear that, upon entering office, he would use the military to help fix the southern border crisis. He has been doing so in various ways, and this is the latest example.

In the memo, the White House writes, "Our southern border is under attack from a variety of threats.  The complexity of the current situation requires that our military take a more direct role in securing our southern border than in the recent past."

"Through Executive Order . . . I assigned the Armed Forces . . . the military missions of repelling the invasion and sealing the United States southern border from unlawful entry to maintain the sovereignty, territorial integrity, and security of the United States," it continues.

The rest of the memo lays out further details about how this mission is going to be carried out.

The Trump administration makes it clear that, in its view, Trump has the power from the Constitution to take the step.

More details:

According to Fox, the land that the military will take over spans three states.

Per the outlet:

The memorandum . . . directs the secretaries of Defense, Interior, Agriculture and Homeland Security "to provide for the use and jurisdiction by the Department of Defense over such Federal lands, including the Roosevelt Reservation and excluding Federal Indian Reservations, that are reasonably necessary to enable military activities."

The three states include California, New Mexico, and Arizona. This is land that Theodore Roosevelt, way back in 1907, designated as federal land for the very purpose of keeping the southern border secure, and this is exactly what the U.S. military will be doing.

Once the military gets there, part of its mission will be to build a "border barrier" and to place "detection and monitoring equipment." The land will essentially become a "military installation," and it will get the designation of a "National Defense Area," one where "military activities" occur.

As for what "military activities" will be taking place, the memo states that it will be any activities the secretary of defense determines to be " reasonably necessary and appropriate to accomplish the mission" of securing the border.