HELENA, Mont. (AP) _ Gay rights advocates, whose efforts to enact a law that would outlaw discrimination against gays and lesbians failed two years ago, are reviving the issue. Sen. Christine Kaufmann, an openly gay Helena Democrat, is sponsoring a bill that would add ''gender identity or expression'' and ''sexual orientation'' as categories under the laws prohibiting discrimination. The laws currently cover race, religion, gender and other areas. Kaufmann said her proposal makes good on promises of equality laid out in the state and U.S. constitutions. She compared the measure to the civil rights movement. ''When we as a society...