(1) In any felony case, the court may impose a minimum term of imprisonment of up to one-half of the sentence it imposes.
(2) Notwithstanding the provisions of ORS 144.120 and 144.780:
(a) The State Board of Parole and Post-Prison Supervision shall not release a prisoner on parole who has been sentenced under subsection (1) of this section until the minimum term has been served, except upon affirmative vote of a majority of three board members or, if the chairperson requires all voting members to participate, a majority of all voting members.
(b) The board shall not release a prisoner on parole:
(A) Who has been convicted of murder defined as aggravated murder under the provisions of ORS 163.095, except as provided in ORS 163.105;
(B) Who has been convicted of murder in the first degree under the provisions of ORS 163.107, except as provided in ORS 163.107 (3) or 163.155 (6) to (8); or
(C) Who has been convicted of murder in the second degree under the provisions of ORS 163.115, except as provided in ORS 163.115 (5)(c) to (f) or 163.155 (6) to (8).