* Bill had difficult road to passage
* "It changed our culture"
* Biden was chief author of original law
President Barack Obama on Thursday reauthorized the Violence Against Women Act, the landmark 1994 law designed to curb domestic abuse, which is now expanded to cover gays, immigrants, Native Americans and sex-trafficking victims.
Obama signed the new version of the law at a packed ceremony at the Interior Department where the event was shifted because the White House could not accommodate all the advocates who supported the measure, the president said.
"One of the great legacies of this law is that it didn't just change the rules," Obama said. "It changed our culture. It empowered people to start speaking out. ... And it made clear to victims that they were not alone, that they always had a place to go, and they always had people on their side.
"And today, because members of both parties worked together, we're able to renew that commitment," he said.
In thanking Democrats and Republicans, Obama was tacitly recognizing the bill's tough path through Congress. Republican lawmakers initially refused to support the measure, and then offered an alternative that advocates said would weaken domestic violence protection for women.
In the end, 87 Republicans in the House of Representatives and 18 in the Senate bucked party leadership to support the law and send it to Obama for his signature.
The U.S. Conference of Catholic Bishops opposed the new law, objecting to the mention of "sexual orientation" and "gender identity."
"These two classifications are unnecessary to establish the just protections due to all persons," the bishops said in a statement.
Obama thanked Vice President Joe Biden, the chief author of the original Violence Against Women Act two decades ago when he was a senator. There has been a 64 percent drop in domestic violence in the past 10 years, according to Justice Department statistics.
HELP FOR NATIVE AMERICANS, SEX-TRAFFIC SURVIVORS
Biden was introduced by Diane Millich, founder of Our Sister's Keeper, an organization founded in 2007 to decrease violence against Native American women using tribal traditions. Millich, a member of the Southern Ute Indian Tribe in Colorado, is a domestic abuse survivor, although her case was never prosecuted because her abuser was a non-Indian.
The updated law ensures that abusers of American Indian women can be arrested and prosecuted on Indian lands.
Obama praised Tysheena "Tye" Rhames, who was recruited into the sex trade by a neighbor at the age of 12 and rescued two years later. She is now enrolled in college and working with at-risk girls in New York City.
"So with this bill, we reauthorize the Trafficking Victims Protection Act to help more girls turn out like Tye," he said.
Since abused women have a heightened risk of being killed, the law mandates screening for homicide risks and requires states to work to reduce domestic violence deaths.
Lesbian, gay, bisexual and transgendered victims of domestic violence have a harder time seeking shelter and other services, so the new law makes those services more accessible and protects people seeking such help from discrimination.
The law also addresses the issue of immigrants who might be reluctant to report abuse because their immigration status may be in question. The law improves existing protections for immigrants by supporting better access to life-saving services and encouraging more victims to cooperate with law enforcement.
The predominantly female audience gave Obama and Biden standing ovations and repeated applause. Obama won a second term last November, receiving 55 percent of the women's vote.