If Trump sends the National Guard into cities without the consent of governors, state leaders would be able to file court challenges, as California Governor Gavin Newsom did to block Trump from federalizing the National Guard to quell protests and riots over his immigration policy in Los Angeles earlier this summer, Banks said.

The president’s comments follow his statements Friday when he raised the idea of using the Guard in Chicago, as he previously did in Los Angeles and currently is doing in Washington, D.C.