Minn. Stat. § 518.01: VOID MARRIAGES.

All marriages which are prohibited by section 517.03 shall be absolutely void, without any decree of dissolution or other legal proceedings; except if a person whose spouse has been absent for four successive years, without being known to the person to be living during that time, marries during the lifetime of the absent spouse, the marriage shall be void only from the time that its nullity is duly adjudged. If the absentee is declared dead in accordance with section 578.17, the subsequent marriage shall not be void.