Illinois constitution
Article IV
Section 14

The House of Representatives has the sole power to
conduct legislative investigations to determine the existence
of cause for impeachment and, by the vote of a majority of
the members elected, to impeach Executive and Judicial
officers. Impeachments shall be tried by the Senate. When
sitting for that purpose, Senators shall be upon oath, or
affirmation, to do justice according to law. If the Governor
is tried, the Chief Justice of the Supreme Court shall
preside. No person shall be convicted without the concurrence
of two-thirds of the Senators elected. Judgment shall not
extend beyond removal from office and disqualification to
hold any public office of this State. An impeached officer,
whether convicted or acquitted, shall be liable to
prosecution, trial, judgment and punishment according to law.