I could see expanding the role of the US Border Patrol if it became necessary. But as far as I know, there are no attacks or depredations against US civilians or their property on this side of the border. The state governors do have ANG troops at their disposal to maintain L&E. The president could and should beef up the Border Patrol and if Congress agrees then the BP's charter could be amended as needed. But using US federal troops for law enforcement purposes on the border or anywhere else is a tricky business that could eventually lead to an oppressive police state. It's been done before:
George H.W. Bush was the last president to use the Insurrection Act, a response to riots in Los Angeles in 1992 after the acquittal of the white police officers who beat Black motorist Rodney King in an incident that was videotaped.
But that incident was confined to one city, whereas the 2020 riots were widespread. I don't think it's a good idea to have the US Army patrolling the streets of any and every major city. If the respective city and state officials who are charged with maintaining law and order do not request assistance, then as far as I'm concerned the citizens and voters therein are getting the gov't they voted for and deserve. And the rest of us shouldn't be paying anything to repair and rebuild after the damage is done.