Until the recent advent of the "no-fault" divorce, in which neither party is expected to prove the spouse as the "guilty party" in the marriage, a marriage could be dissolved only for what the state deemed to be proper grounds. While "no-fault" divorces have become increasingly common in all U.S. states, there are still many cases where marital partners seek to establish fault, particularly in states that require a waiting period of legal separation before allowing a "no-fault" divorce. The most common grounds are adultery, desertion, and physical or mental cruelty. Habitual drunkenness, incurable mental illness, conviction of a crime, nonsupport, or constructive abandonment are other grounds for establishing fault. Corrupt consent by a party to the conduct of the other party bars a divorce, as does collusion. Forgiveness of the offense, either express or implied (as by cohabitation), on condition that it not be repeated, is a bar to a divorce for that offense.