WASHINGTON, DC – Defense Secretary James Mattis and Homeland Security Secretary Kirstjen Nielsen announced in a joint statement on Friday that the first 500 troops are moving to the U.S.-Mexican border after Attorney General Jeff Sessions declared “zero tolerance” for illegal crossings, followed on Saturday by a tweet from President Trump making clear that these actions are part of an interagency response to seal the border.

“We are sealing up our Southern Border,” President Trump tweeted on Saturday afternoon. “The people of our great country want Safety and Security. The Dem[ocrats] have been a disaster on this very important issue.”

We are sealing up our Southern Border. The people of our great country want Safety and Security. The Dems have been a disaster on this very important issue! — Donald J. Trump (@realDonaldTrump) April 7, 2018

Mattis signed an order that could deploy up to 4,000 National Guardsmen to America’s southern border. The first 500 troops deployed this weekend.

He and Nielsen then issued a joint statement on the operation, showcasing that this is an interdepartmental operation.

“Tonight, National Guard troops are deploying to support border security missions along the U.S. southwest border,” Mattis and Nielsen begin. The secretaries add that they “are committed to using every lever of power to support the men and women of law enforcement defending our nation’s sovereignty and protecting the American people.”

This comes on the heels of Attorney General Jeff Sessions’ issuing a memorandum to U.S. attorneys in federal districts on the southern border, ordering a zero-tolerance policy for illegal border crossers. Sessions ordered that the Department of Justice will prosecute illegal border crossings, which are a crime under 8 U.S.C. § 1325(a).

Sessions’ memo this week highlights, “Congress has failed to pass effective legislation that serves the national interest—that closes dangerous loopholes and fully funds a wall along our southern border.”

These actions show what the president can do under existing law without Congress. Section 3 of a presidential memorandum President Trump signed on April 4 ordered the Departments of Defense, Homeland Security, and Justice to coordinate the details to promptly deploy National Guard troops to the border.

As former Secretary Ken Blackwell opined last week, these actions show President Trump using the full range of resources at his disposal to tackle illegal immigration and secure the border, revealing a “unified Trump policy.” Less than a week later, troops are on the move.

Ken Klukowski is senior legal editor for Breitbart News. Follow him on Twitter @kenklukowski.