A recent update to an existing order signed on October 3, 2019, has increased speculation that the government is preparing for civil unrest.
Several commentators have referenced the document as a sign that the Executive Branch is preparing to call upon the Marines, should civil unrest start to get out of hand.
In fact the order is nothing new, but serves as an update to the previous order published in 2014. The document titled, Marines (Reserves) Ordered To Active Duty ISO Defense Support Of Civil Authorities, stipulates that the President can call upon the Marine Reserves to support the National Guard in the case of a national emergency. It clarifies who is in command and for how long reserves can be called upon to act in a support role.
Recent comments by House Representatives calling for the impeachment of the President, despite not having identified the laws broken or having the votes to do so, as well has many media commentators increasing their rhetoric against the elected President, are adding to the speculation that this maybe a defensice move on the part of the Executive Branch. While it does bring the ruling up to date, should the opposition to the Whitehouse try to overeach their authority, it really is nothing more than an update to an already established procedure.
The purpose is to be enable limited use of the military when needed to support and aid Americans in a time of need.
If you want to read the document you can find it here