It was waiting to happen.  The topic is DOMA or Defense of Marriage Act.  The issue is discrimination.  The court has consistently found that a court CAN discriminate if it meets certain criteria.  They are in different levels or categories of discrimination.   For example, some laws must be rationally related to furthering a legitimate government interest. In applying the rational basis test, courts begin with a strong presumption that the law or policy under review is valid.
When some constitutionally suspect classifications (race, religion, alienage, or national origin) are not at issue, nor are any fundamental constitutional rights at stake, a [...]