PHOENIX — Unwilling to wait for a 2016 vote, advocates for same-sex marriage asked a federal judge Thursday to rule the state’s ban is illegal.

The lawsuit challenges longtime state laws and a voter-approved 2008 state constitutional amendment defining marriage in this state as solely between one man and one woman. Jennifer Pizer, senior counsel for the Lambda Legal Defense and Education Fund, representing seven Arizona couples and two survivors of same-sex relationships, contends that ban violates federal constitutional provisions.

“Because our clients are not able to marry, they’re being denied equal protection under the laws, which should be a birthright of all Americans,” she said at a Phoenix news conference detailing the legal action.

Attorney General Tom Horne said he thinks the Arizona law is legally defensible.

Horne sidestepped the question of whether allowing heterosexual couples to marry but denying that right to same-sex couples amounts to unequal treatment. He said that’s not the legal issue. “The question really is, what is the definition of marriage,” he said.

“I would say that the Legislature, and the people acting through the Legislature, have a right to define what is marriage,” Horne continued. “And that should be a decision made by the people governing themselves rather than the judiciary imposing it on them.”

The lawsuit comes as proponents of same-sex marriage are gearing up to put…