By Julia Preston
LOS ANGELES — They pushed strollers, tugged toddlers and streamed into the convention center in the heart of this city on Sunday, thousands of immigrants here illegally and anxious to find out if they could gain protection from deportation under executive actions by President Obama.
The crowd, waiting in a long snaking line to check in, was drawn by an information session organized by advocacy groups offering people initial assessments to see if they meet the requirements to apply to stay in the country and work. The day became a kind of coming-out party for about 5,000 unauthorized immigrants, the largest gathering in the country of people who might qualify for temporary protection since the president’s announcement last month.
Delfina Ibarra, 40, from Mexico, was taking in information while nursing a 17-month-old, Kimberly, the newest citizen in the family. Ms. Ibarra, who has lived in California for 23 years, said she also has a 21-year-old son who is a citizen. She said that without documents, she has been limited to cleaning houses and packing crates in industrial distribution centers. With a legal deferral document and a work permit, Ms. Ibarra said, she could get a driver’s license and go back to school.
“It’s never too late to start again,” she said, laughing and holding up her baby.
Immigration advocates convened the information session in downtown Los Angeles not just to give out information but to galvanize their supporters as Republicans, angered by what they see as an illegal power grab by Mr. Obama, say they will seek to halt the programs when they gain control of both houses of Congress next year. Texas was joined by more than 20 other states, most led by Republicans, in filing a lawsuit to stop the president’s actions, arguing he exceeded his constitutional authority.
Hundreds of activist leaders also converged here for a three-day strategy conclave to plot how to enroll a maximum number of people in order to create momentum among immigrants and Latinos so they will defend the president’s actions and try to stop Republicans from canceling the programs before they get off the ground.
“We’re telling all our families to get ready to apply if they qualify, because the more families apply, the harder it is for Republicans to take it away,” said Angelica Salas, the executive director of the Coalition for Humane Immigrant Rights of Los Angeles, one of the main groups organizing the event.
Mr. Obama will offer three-year deportation deferrals and work permits to at least 3.5 million immigrants who have been living in the United States for five years, have no serious criminal records and have a child who is an American citizen or legal permanent resident. The president also expanded a 2012 program for young immigrants. The federal agency in charge, Citizenship and Immigration Services, will begin in mid-February to accept applications for the youth program. Applications by the parents will begin in mid-May.
Many who lined up beginning at 7 a.m. and flocked into a vast hall of the Los Angeles Convention Center said they would have no trouble proving their histories in this country. When organizers asked how many Mexicans were in the room, thousands of hands shot up. Two-thirds of the immigrants eligible nationwide will be from Mexico, according to Pew Research Center.
One of them, Rigoberto Esparza, 50, said that he had been in the United States for 22 years and that all three of his children were citizens born here.
Mr. Esparza said he worked in construction, employed by a framing and drywall company. He added that he was not worried about declaring his status at the meeting because he was confident he would qualify for the White House program.
“I have been so many years in this country, if they give us a chance to get right with the law, we have to take advantage of it,” Mr. Esparza said.
He was walking on crutches, after a fall on the job left him with a broken ankle. He said his employer helped him obtain workers’ compensation for his medical costs, but the accident reminded him that he remained vulnerable without documents.
The orientation slide show projected on big conference hall screens began with unflattering photographs of Speaker John A. Boehner of Ohio and of Representative Kevin McCarthy, a Republican from California who is also in the House leadership. It emphasized the message that Republicans were responsible for the failure in Congress to pass a broad overhaul of immigration policy that would have provided a permanent pathway to citizenship.
“These are the ones who keep getting in the way of immigration reform,” Ms. Salas said from the stage.
When a photograph appeared of Mr. Obama at his Oval Office desk, the crowd erupted in applause. It was an abrupt change for an immigrant community that has held countless protests criticizing the president for his record on deportations.
“Republicans have shown they are not on the side of the immigrant,” said Dany Santos, 35, an immigrant from Guatemala who came with a double stroller for his two American-born children, 3 and 4 years old. Still, he said he thought the program could have been better. “The news is fifty-fifty,” he said, “good for us but not good for so many people we know were left out” because they did not have children born in this country.
Mr. Santos’s wife, Virginia, who is also in the United States illegally, said she worked as a longtime babysitter for several Los Angeles families. She said she and her employers would be relieved if she had a legal work permit.
Republicans have said Mr. Obama ignored the results of the midterm elections, in which his party had large setbacks, taking sweeping executive actions instead of waiting for Congress to set its path on immigration. A spending bill that received final approval in the Senate late Saturday funds the Department of Homeland Security only to the end of February, so the Republican-led Congress can then revisit ways to defund or cancel Mr. Obama’s initiatives.
Joshua Hoyt, the executive director of the National Partnership for New Americans, said groups gathered here were laying plans to sign up at least 500,000 immigrants for the president’s program. Advocates also appealed to immigrants here illegally who cannot vote to contact people who can.
“All those children are going to be voters,” Ms. Salas said, “and those voters are going to remember who stood with their dad and their mom.”