Quo warranto and impeachment are two distinct proceedings, although both may result in the ouster of a public officer. Strictly speaking, quo warranto grants the relief of "ouster", while impeachment affords "removal."

A quo warranto proceeding is the proper legal remedy to determine a person's right or title to a public office and to oust the holder from its enjoyment. 11 It is the proper action to inquire into a public officer's eligibility12 or the validity of his appointment. 13 Under Rule 66 of the Rules of Court, a quo warranto proceeding involves a judicial determination of the right to the use or exercise of the office.

Impeachment, on the other hand, is a political process undertaken by the legislature to determine whether the public officer committed any of the impeachable offenses, namely, culpable violation of the Constitution, treason, bribery, graft and corruption, other high crimes, or betrayal of public trust. 14 It does not ascertain the officer's eligibility for appointment or election, or challenge the legality of his assumption of office. Conviction for any of the impeachable offenses shall result in the removal of the impeachable official from office. 15