The Idaho State Constitution states that "a marriage between a man and a woman is the only domestic legal union that shall be valid or recognized in this state." Art. III § 28. This means that the Idaho Constitution prevents same-sex marriages from being performed in Idaho, and it also prevents same-sex marriages that were performed in other states from being recognized in Idaho. On October 07, 2014, however, the Ninth Circuit of the United States Court of Appeals made a decision that legalized same-sex marriage in the state of Idaho.
In the decision, the Court determined that the Idaho law violates the Equal Protection Clause of the Fourteenth Amendment because the law allows for opposite-sex marriage while denying the same privileges to same-sex couples. The Court ruled that because Idaho's law discriminates on the basis of sexual orientation, that it deserves a higher level of scrutiny than rational basis scrutiny. The Court concluded that Idaho's same-sex marriage laws do not meet this heightened level of scrutiny, therefore, the marriage laws were struck down.
Shortly after the Circuit Court opinion, the State of Idaho asked the United States Supreme Court for a stay which was granted by Justice Kennedy. This stay temporarily prevented same-sex marriages from taking place in the state of Idaho until Idaho officials had the opportunity to argue their case to the Supreme Court. The Supreme Court lifted the stay and as of October 15, 2014, same-sax marriages are recognized, and may now be performed in Idaho.