Last Call

I'm no law perfesser, but this here?

A judge in Washington, D.C., has thrown out a lawsuit by opponents of gay marriage against the city's elections board.

Plaintiffs led by a Maryland pastor, Bishop Harry Jackson, sued after the Board of Elections and Ethics refused to put their initiative on the ballot. The measure would have defined marriage as between a man and a woman. The board ruled it violated the city's Human Rights Act.

D.C. Superior Court Judge Judith N. Macaluso ruled Thursday in favor of the city. She said the board's action was justified because the initiative would in effect authorize discrimination.

Why hasn't that argument been used to basically overturn every state gay marriage ban on the books? Can anyone explain that to me?  Is that what the basic argument is in the California Prop 8 trial?  If so, wouldn't that be the basis of the argument before the Supreme Court when it gets there?