By Steve Quinn
JUNEAU Alaska (Reuters) - A U.S. federal judge on Sunday ruled that the state of Alaska's ban on same-sex marriage was unconstitutional.
Judge Timothy Burgess of the U.S. District Court for Alaska made the ruling after hearing oral arguments on Friday challenging the state's 16-year-old ban, saying it added to discrimination already faced by gay and lesbian people every day.
"Alaska's denial of the benefits and dignity of marriage for them only perpetuates this discrimination without legitimate grounds," Burgess wrote.
He also barred Alaska from refusing to acknowledge lawful same-sex marriages conducted in other states.
Alaska Governor Sean Parnell said Sunday that the state would appeal the ruling, saying the constitutionality question was in flux.
"As Alaska's governor, I have a duty to defend and uphold the law and the Alaska Constitution," Parnell, a Republican, said.
Five couples, four of whom already had legally married in other states and a fifth wishing to marry in Alaska, filed their suit against the state in May challenging the ban.
In 1998, Alaska voters enacted a constitutional amendment that excludes same-sex couples from marriage.
The state contended that the voters should have the final word, not the courts.
Burgess disagreed, writing that the state's right to define marriage "is not unbounded."
"A state may not exercise its power to define marriage in a way that infringes upon individuals' constitutional rights," he wrote.
Sunday's ruling caps off a busy seven days in federal court rulings on same-sex marriage.
On Tuesday, the 9th U.S. Circuit Court of Appeals struck down same-sex marriage bans in Nevada and Idaho.
A day earlier the U.S. Supreme Court let another appeals court ruling stand to allow similar marriages.
On Sunday, Burgess' 25-page ruling cited the need to bring an end to longstanding discrimination.
Joshua Decker, an attorney for the American Civil Liberties Union of Alaska, hailed the decision.
"Alaska had the misfortune of being the first state, in 1998, to ban equal marriage and bake discrimination into our constitution," he said. "This victory brings equal rights to thousands of Alaskan couples who are in loving, committed relationships."
(Reporting by Steve Quinn; Editing by Frank McGurty, Sharon Bernstein and Eric Walsh)