To answer your question:

https://www.bbc.com/news/articles/c9qwez9zz7jo

The Insurrection Act of 1807 allows the president to use active-duty military personnel to perform law-enforcement duties inside the US.

Once invoked, troops could be tasked with a range of duties, from quelling civil unrest and enforcing court orders to arresting and detaining migrants.

Because the Insurrection Act was written in broad terms, with little specific guidance on how and when the powers can be used, it gives presidents wide latitude in deciding when to mobilise military personnel for domestic operations.

Time to bring in the army to oppress the citizenry. Hoo rah!