From a public election law listserv today:
Apparently, John McCain announced today that he would fire the SEC Chair, because the SEC Chair serves "at the appointment of the President."
The SEC, however, is what is known legally as an independent agency. The sine qua non of such an agency is that its members do not serve at the appointment of the President; they do not serve at the pleasure of the President, to use another common formulation. By law, the head of the SEC can only be "fired' for a specific set of "good cause" reasons that are defined in the statute. If we had the kind of unitary executive branch that some advocates prefer, the President would have complete discretion to fire the head of the SEC. But we do not have such a system, unless we someday reverse the last 70 years of constitutional law.