You will hear people say that due to pollination, air pollution, or the intervention of the Alien Overlords (OK. I made that last one up. But people get a little extremist at times) there is no such thing as organic food any more.
Yes, any government official can be impeached - Presidents, Legislators & Judges, etc. But you can't impeach people for doing a bad job. Impeachment is necessarily dependent upon a charge of criminal or significant unethical behavior to warrant removal. Yes, Granholm is awful, but we're stuck with her for 4 more years.
There are only two impeached presidents in United States history, meaning only two presidents have been charged by the House of Representatives with committing high crimes and misdemeanors. Neither of the two impeached presidents, Andrew Johnson and Bill Clinton, were convicted by the Senate. In fact, there has never been a president removed from office using the impeachment process. There is only one other mechanism set forth in the U.S. Constitution, aside from conviction on impeachment charges, that allows for the removal of a failing president.