Marriage is a vital social institution. The exclusive commitment of two individuals to each other nurtures love and mutual support; it brings stability to our society. For those who choose to marry, and for their children, marriage provides an abundance of legal, financial, and social benefits. In return it imposes weighty legal, financial, and social obligations. The question before us is whether, consistent with the Massachusetts Constitution, the Commonwealth may deny the protections, benefits, and obligations conferred by civil marriage to two individuals of the same sex who wish to marry. We conclude that it may not. The Massachusetts Constitution affirms the dignity and equality of all individuals. It forbids the creation of second-class citizens. In reaching our conclusion we have given full deference to the arguments made by the Commonwealth. But it has failed to identify any constitutionally adequate reason for denying civil marriage to same-sex couples. --GOODRIDGE, et al. v. DEPARTMENT OF PUBLIC HEALTH, et al.