Ok. Is he going to send government handlers with any scientists presenting papers to make sure they toe the line?
Don't worry, we've always had government handlers following us around to make sure we toe the line. It's one of the worst parts of this job.
Usually "the line" is pretty easy. Stick to the facts, represent your agency with dignity and professionalism, articulate your findings in language people can understand, and try not to piss people off. The only political pressures I've felt in this job have been about internal power struggle between agencies, not national politics intervening with facts.
Some of my colleagues at other agencies were deep sixed under the Bush administration, but I haven't heard of a single instance of the executive branch interfering in federal research under Obama. That doesn't mean it didn't happen, just that I haven't heard about it the way I used to hear about Dick Cheney sending cease and desist letters to researchers.
I think today's EPA ban will be temporary, while they figure out what leverage they have to control their communications officers, and will be lifted once they restrict access to Twitter to people who have sworn the loyalty oath or whatever.