Biden or Harris could revoke his security clearance, which would seriously hamper his position at SpaceX due to all the DoD contracts. The report that Elon talks to Putin regularly is enough of a concern to justify that move.
Biden or Harris could also order an investigation into Elon’s citizenship application. If it is found he lied during that process, his citizenship could be revoked. The reports that he worked illegally before gaining citizenship are enough to justify an investigation but I didn’t know if that would be a disqualifier.
Either way, Elon relies heavily on the US government (DoD contracts, EV tax credits, etc) and needs to be reminded that choices have consequences. Just look at Bezos - don’t think Amazon AWS losing the $10 billion JEDI contract after criticizing Trump didn’t affect his decision to prevent the Washington Post from recommending Harris.
Basically - don’t slap the hand that feeds you.