A memo issued by the Department of Defense this week allows civilian employees of the agency to take part in missions run by the Department of Homeland Security.

The memo — issued by Defense Secretary Pete Hegseth — says civilian defense personnel will support Homeland Security operations at the southern border and with internal immigration enforcement.

Posse Comitatus is a legal principle that forbids the military from taking part in law enforcement. But, as Syracuse University professor William Banks says, this direction is for Defense employees who aren’t military.

“This is a step that avoids that problem, that is the legal problem, and potentially adds many thousands, tens and perhaps hundreds of thousands of employees on a temporary basis,” he said.

Banks says defense personnel would be deputized to do immigration-related work through 287-G agreements — that’s the same arrangement that allows local jurisdictions to work with ICE within county jails and other sites.

Banks says it’s another step the Trump administration is making to achieve its stated goal of 1 million deportations a year.

“As we all know in the first four months, the promise has been out there, but the personnel to carry it out, or the wherewithal, hasn’t matched the rhetoric at all,” he said.