Once elected for a four-year-term, Federal Councillors can neither be voted out of office by a motion of no confidence nor can they be impeached. Re-election is possible for an indefinite number of terms, and it has historically been extremely rare for Parliament not to re-elect a sitting Councillor. This has only happened four times - to Ulrich Ochsenbein in 1854, to Jean-Jacques Challet-Venel in 1872, to Ruth Metzler-Arnold in 2003 and to Christoph Blocher in 2007. In practice, therefore, Councillors serve until they decide to resign and retire to private life, usually after three to five terms of office.