Today, as part of a massive national mobilization calling for immediate immigration reform, New York organizers are striving to follow California’s lead and show more immigrant muscle.

As Congress has struggled to fix the nation’s broken immigration system, mass mobilizations have drawn record numbers of immigrants in cities across the country: Last month, Chicago saw 30,000; Los Angeles, in the largest rally in its history, drew more than half a million.

New York, meanwhile, has elicited paltry turnouts in comparison, with thousands at most.

Immigrant organizers say the problem in large part has been that New York has too many different kinds of immigrants. While the city’s population of foreign born, nearly 40%,is similar to that of Los Angeles, its diversity dwarfs its West Coast rival. New York’s immigrant population is almost evenly divided among Asians, Europeans, and Caribbean, each bringing in about 20% of the population. Latin America is slightly larger at 32%, but still does not dominate, compared to being the source of almost half of the nation’s immigrants.

When Los Angeles and Chicago organized in mass numbers, the rallies were largely Latino and driven by the Spanish-language disc jockeys and Catholic Church. In New York, a unified immigrant voice has been difficult to come by. “New York is hard because there are so many countries: There are the Russians, the Turkish, the Egyptians, the Filipinos, the Taiwanese, the Koreans,” the spokeswoman for the Queens Hispanic Chamber of Commerce and an organizer for the event, Nyddia Lugo-Spahr, said. “Everyone here just does it by nation and ethnicity. There is no leader of the majority.”

The organization founded to serve that function, the New York Immigration Coalition, has found itself struggling to reconcile groups’ different interests, even on an issue that seems as clear cut as immigration reform for immigrant interests.

“We don’t have a single dominant ethnic group, like Mexicans,” the executive director of the New York Immigration Coalition, Chung-Wha Hong, said. “Even Dominicans, who are the largest, are under 25%, which means that in order to turn out numbers here we’re going to have to saturate all the communication numbers and networks in about 10 different communities.”

While she said diversity brings strength, and highlights the complexities of immigration reform, it is also a challenge. A Mexican audience will be most interested in legalization programs, a Russian family unity, and an Arab enforcement measures, she said.

Another contributing factor is New York has not had a history of struggle over legislation that cracks down on immigrant benefits, such as Proposition 187 in California. The city has gone in the opposite direction, with Mayor Bloomberg speaking out on immigration reform and passing Executive Order 41, which created a “don’t ask, don’t tell” policy with regard to public officials inquiring about immigration status except in criminal investigations. Ms. Hong, however, takes issue with the idea that New York is an immigrant-friendly city and that is the reason the demonstrations have not taken place.

“There’s also this myth that New York’s different from L.A. or other places,” she said. “I think the mainstream still sees this nice image of diversity and immigrants doing well but does not see some of the built-up fear and sense of urgency and fear.”

The tens of thousands of New York immigrants who are expected to descend on City Hall this afternoon, Ms. Hong said she has noted, have observed the lesson from the Los Angeles protests with a “new sense of civic empowerment.”

“I think it’s the biggest transformations we’ve seen on the immigration debate,” she said. “It’s been the best civics lesson immigrants have ever had, to see the grassroots actions translate directly to legislative change.”

Before a Los Angeles rally on March 25 drew more than half a million peaceful marchers, legislation in the Senate’s Judiciary Committee looked poised for failure. When the committee reconvened two days after the rally, the bill was swiftly passed, including provisions that were favorable to immigrants. Based on legislation introduced by Senator McCain, a Republican of Arizona, and Senator Kennedy, a Democrat of Massachusetts, the bill included a path to legalization for the nation’s 12 million illegal immigrants, a new temporary worker program that would bring 400,000 new guest visas a year, and beefed-up enforcement.

The celebrations among immigrants that followed that passage, however, died when quarreling over amendments train-wrecked an immigration bill the day senators left for their two-week recess last week. As senators return to their home states without a bill in hand, they will encounter an electorate deeply divided over immigration.

Today, the voices that will be loudest will be those of the hundreds of thousands of immigrants and their advocates, organized by community and student groups, ethnic press outlets, business interests, and labor unions, loudly demonstrating today in cities across the country demanding the Senate pass a bill immediately. Called a National Day of Action for Immigrant Rights, the demonstrators’ anger over House legislation that criminalizes immigrants will be heightened by the collapse Friday of the delicately crafted Senate legalization. Rallies, vigils, and walkouts are planned across the country, from rural migrant worker towns to a mass rally expected to draw more than 100,000 marchers to the Capitol in Washington.

In New York, in order to reach out to the diverse groups, a variety of tactics has been employed, from radio appearances to church meetings, drawing the involvement of 200 organizations.

One method has been the use of the Latino disc jockeys, with two of the city’s two major Spanish radio outlets signing on as sponsors last week. Since then advertisements have run at frequent intervals prodding listeners in Spanish as “the new pilgrims” to show “the flag of the country they love” and turn out today at City Hall. Haitian, Korean, Chinese, Russian, and other press outlets have all been contacted.

State Attorney General Eliot Spitzer and Senator Schumer will join an array of representatives, local politicians, and labor leaders. Students are expected to walk out from a dozen high schools and universities, and thousands will end work early to attend.

Despite today being a workday, Ms. Hong said she expects the turnout to be larger than the Immigrant Workers Freedom Ride Rally in Queens, which rivaled the largest immigrant rights demonstrations the city has ever seen. That rally, in October 2003, which was estimated to have turned out 70,000 for the conclusion of a moving demonstration based on the Freedom Rides of the civil rights movement, was intended to usher in a new era of consciousness for immigrant rights. Little seemed to happen directly after that rally, but in the last few weeks there has an incredible transformation in public awareness and legislative action. “Back then we were telling people this is an important issue, you have to address it,” Ms. Hong said. Now, she said, “stakes are high and decisions are being made that could either set us on the road to like a whole new system that is going to work for us for the next several decades, or just piling on and deepening the crisis.”