Sorry, but this is an irrelevant point. There is a precedent for courts to remove ineligible candidates. That would superceded an impeachment.
I never said nor implied that the de facto officer doctrine “pre-empt(ed) anyone from being removed from office if they are not eligible.” In fact, my point is that the de facto officer doctrine is precisely why an allegedly ineligible office holder can be impeached, tried, convicted and removed.
I was talking about being removed by a court, not by the legislative branch. Your suggestion was that the courts wouldn't or couldn't do this, but there is a precedent. And as for your claims, you have still have provided no precedent.
There are no “candidates” at the moment. The next presidential election is in 2016.
The only ways to remove a sitting president from office are by losing an election, impeachment, trial and conviction, resignation, and infirmity or death.
“In 1973, the Department of Justice concluded that the indictment and criminal prosecution of a sitting President would unduly interfere with the ability of the executive branch to perform its constitutionally assigned duties, and would thus violate the constitutional separation of powers. No court has addressed this question directly, but the judicial precedents that bear on the continuing validity of our constitutional analysis are consistent with both the analytic approach taken and the conclusions reached. Our view remains that a sitting President is constitutionally immune from indictment and criminal prosecution.”—”A Sitting President’s Amenability to Indictment and Criminal Prosecution”
http://www.justice.gov/olc/sitting_president.htm