Kelly Glossip was in a same-sex relationship with Missouri Highway Patrol Cpl. Dennis Engelhard for nearly 15 years when Engelhard was hit by a car on an icy interstate on Dec. 25, 2009, the St. Louis (Mo.) Post-Dispatch reported Wednesday.
Maurice B. Graham, Glossip's attorney, described the relationship between the two men as "almost synonymous with opposite-sex, husband and wife."
Graham argued the 2001 law at the center of the legal challenge set up a special category based on sexual orientation.
Assistant Attorney General James R. Ward defended the ban. "this is not a special law," he said. "It's open-ended because the class as described is for spouses."
Supreme Court Judge Laura Denvir Smith noted gays are not allowed to marry in Missouri.
Ward argued allowing same-sex partners to receive survivor benefits would have "tremendous ramifications" on the state's pensions plans.
Graham countered the criteria for domestic partner benefits could be "very, very carefully drawn" to ensure that only long-term relationships were covered.