President Obama's decision Wednesday to stop defending a law banning federal marital benefits for same-sex couples will boost an array of court challenges to the measure, including two in the Bay Area by gay and lesbian government workers seeking insurance coverage for their spouses.

It could also strengthen the case against states' prohibitions on same-sex marriage, including California's Proposition 8. Although the Justice Department has not taken a position on those measures, its newly stated position - that the government cannot support laws tilted toward heterosexuals without a strong justification - is central to the marriage cases.