Who is in charge of the executive branch of government?

That’s the only question you need to answer in order to understand the controversy over President Trump ordering certain federal agencies’ Twitter accounts to stop making pronouncements in the government’s name. Presumably, this restriction will last only until the agencies’ new directors and secretaries are in place. Or maybe not. (Frankly, very few government social media accounts are probably worth the cost of running them, but that’s for another day.)