The three-hour hearing is a critical legal test for both sides. But opponents of Proposition 8 also used Thursday's hearing as a prime moment to rally their forces and demonstrate resilience after a stinging election loss that many among them believe could have been avoided.

"It's a need for the community to show that we will not be passive participants to our own struggle," said Kate Kendell, executive director of the National Center for Lesbian Rights , one of dozens of gay and civil rights leaders on the scene Thursday morning. "I think it goes to the heart of what we've seen since Nov. 5, and what we've come to appreciate as the critical importance of everyone stepping up and stepping out."