OK so when the social media sites ignore his Executive Order then what? It’s not a law so they can’t be prosecuted. He can’t order them shut down. What will Trump do? Refuse to use Twitter or Facebook?
Initiate anti-Trust proceedings, and strip them of Platform privileges, making them civilly liable for content like any other publisher.
The government is so big these days it is inevitable that Twitter and Facebook have some sort of government contract, loan, grant in there somewhere, particularly if you include any affiliates, business partners, members of the board of directors and/or major shareholders and/or senior executives.
That is the wedge, if Trump is smart enough to find it and use it.
I expect there will be an adjustment of common-carrier and liability laws.
Basically: either let everyone post, or be liable for any illegal post.
Yes there are laws which can be prosecuted, just bead to tweak rules about how they apply.