N.J. Const. art. VII, § III, ¶ 2
The General Assembly shall have the sole power of impeachment by vote of a majority of all the members. All impeachments shall be tried by the Senate, and members, when sitting for that purpose, shall be on oath or affirmation "truly and impartially to try and determine the charge in question according to the evidence". No person shall be convicted without the concurrence of two-thirds of all the members of the Senate. When the Governor is tried, the Chief Justice of the Supreme Court shall preside and the President of the Senate shall not participate in the trial.