SAN FRANCISCO — The labor movement, the faith community, a broad spectrum of immigrant rights organizations and just plain folks joined in a river of 15,000 marchers that flooded city streets from the Mission District’s Dolores Park to the downtown federal building April 23. Observers called it the largest such demonstration in the city to date.

Joining immigrants from Mexico and other Latin American countries behind the Teamsters’ big truck were marchers from the Philippines, South Asia, China, Korea, Ireland and other countries. Their signs and banners protested anti-immigrant legislation now before Congress and proclaimed “Immigrants for a better future,” “Legalization for all” and “Today we march, tomorrow we vote!”

The marchers — brought together by the Bay Area Immigrant Rights Coalition, the National Network for Immigrant and Refugee Rights and other organizations — united around the themes of no criminalization of immigrants, family reunification, workers’ and human rights, and a clear path to legal status.

Fernando Padilla, president of the Latino Student Union at Contra Costa College, said he and other club members were marching to uphold the right of immigrant youth to go to college whatever their status. Padilla said the group wants to go to area high schools to help undocumented youth get the legal, academic and financial aid they need in order to attend college.

Henry Johnson, a former member of ILWU Warehouse Local 6, said he came to the demonstration from Oakland because he believes workers have the same fight and the same enemies, no matter where they are born. Many immigrants are “victims of U.S. imperialism,” Johnson said. “They destroy immigrants’ home economies, forcing them to come here, and then they penalize them for doing so.”

The contingent from Out 4 Immigration, which fights for the right of gays and lesbians to be united with their partners from other countries, included Hans and Phil, currently waging a struggle to stay together. “It’s not just an immigration issue,” said Phil. “It’s a human rights issue. We hope the Uniting American Families Act will add the phrase, ‘permanent partner’ wherever the word ‘spouse’ is mentioned.”

As marchers packed the street in front of the federal building, Nadia Khastagir from the Alliance of South Asians Taking Action told the final rally, “The ‘war on terror’ is inextricably linked with the war on immigrants,” with its targeting and harassment of South Asian, Arab and Muslim communities. “Secret raids, mass detentions and deportations are the weapons of this war.”

“We want fair and just reforms that provide a path to citizenship, and dignity to all immigrants,” she said.

Before the march, an interfaith group of Bay Area clergy gathered at Mission Dolores Basilica. San Francisco Archbishop George Niederauer read a joint statement calling for “a just path to lawful permanent residence and citizenship” and allowing “families torn apart by immigration to reunite.”