For those people who may have been living under a rock or enjoying an extended Tom Hanks-like vacation on a desert island a la Cast Away, the Supreme Court is set to hear argument in four petitions that challenge state laws in the 6th Circuit banning gay marriage. It is widely anticipated that the Justices will finally squarely confront whether banning gay marriage violates the Equal Protection Clause.

The road to the Supreme Court was paved largely by US v Windsor, which struck down the Defense of Marriage Act as a violation of the Fifth Amendment. The decision opened the door for many courts to strike down gay marriage bans. However, states promoting the bans have argued that the Windsor decision makes clear that it is up to states to decide what is a valid marriage and those states could choose to define marriage as only being between a man and a woman. Adding to the confusion is the fact that several states, in an effort to get around the Full Faith and Credit Clause which generally requires states to recognize the legal actions of other states, passed constitutional amendments defining marriage as being only between a man and a woman. A “my constitution trumps yours” argument.

Without a decision based on the Equal Protection Clause, it is likely that there will remain conflicts over the issue. As of today, there are still 13 states in the U.S. where gay marriage is illegal. One of the states where it is legal, Alabama, has become a bit of a constitutional battle ground with a federal court declaring the ban on gay marriage illegal and the state’s Supreme Court issuing an order prohibiting clerks from issuing marriage licenses to same-sex couples.

It is widely anticipated that the Supreme Court’s decision will be in favor of gay marriage. Although the plaintiffs in the case are taking no chances and have pulled out the big legal guns. Lawyers for gay and lesbian plaintiffs have chosen Mary Bonauto, the movement’s pioneer, to argue the case.

Employers should be aware that if the decision is in favor of gay marriage, it may have an immediate impact on policies and benefits. For example, under the FMLA, a spouse would be defined as including same-sex spouses. The Supreme Court’s decision is not expected until June. We will let you know as soon as it is decided.