By Dan Whitcomb LOS ANGELES (Reuters) - Pro-immigration activists say a national boycott and marches planned for May 1 will flood America's streets with millions of Latinos to demand amnesty for illegal immigrants and shake the ground under Congress as it debates reform. Such a massive turnout could make for the largest protests since the civil rights era of the 1960s, though not all Latinos were comfortable with such militancy, fearing a backlash in Middle America. "There will be 2 to 3 million people hitting the streets in Los Angeles alone. We're going to close down Los Angeles, Chicago, New York, Tucson, Phoenix, Fresno," said Jorge Rodriguez, a union official who helped organize earlier rallies credited with rattling Congress as it weighs the issue. Immigration has split Congress, the Republican Party and public opinion. Conservatives want the estimated 12 million illegal immigrants returned to Mexico and a fence built along the border. Others, including President George W. Bush, want a guest-worker program and a path to citizenship. Most agree some reform is needed to stem the flow of poor to the world's biggest economy. "We want full amnesty, full legalization for anybody who is here (illegally)," Rodriguez said. "That is the message that is going to be played out across the country on May 1." Organizers have timed the action for May Day, a date when workers around the world often march for improved conditions, and have strong support from big labor and the Roman Catholic church. They vow that America's major cities will grind to a halt and its economy will stagger as Latinos walk off their jobs and skip school. In California on Thursday, the state senate passed a resolution recognizing "The Great American Boycott of 2006," saying it would educate the United States about the contributions made by immigrants. The measure passed 24-13 along party lines with dissenting Republicans arguing that it sanctioned lawbreaking and encouraged children to skip school. Teachers' unions in major cities have said children should not be punished for walking out of class. Los Angeles school officials said principals had been told that they should allow students to leave but walk with them to help keep order. In Chicago, Catholic priests have helped organize protests, sending information to all 375 parishes in the archdiocese. CRITICS CHARGE INTIMIDATION Chicago activists predict that the demonstrations will draw 300,000 people. In New York, leaders of the May 1 Coalition said a growing number of businesses had pledged to close and allow their workers to attend a rally in Manhattan's Union Square. Large U.S. meat processors, including Cargill Inc., Tyson Foods Inc and Seaboard Corp said they will close plants due to the planned rallies. Critics accuse pro-immigrant leaders of bullying Congress and stirring up uninformed young Latinos by telling them that their parents were in imminent danger of being deported. "It's intimidation when a million people march down main streets in our major cities under the Mexican flag," said Jim Gilchrist, founder of the Minuteman volunteer border patrol group. "This will backfire," he said. Some Latinos have also expressed concerns that the boycott and marches could stir up anti-immigrant sentiment. Cardinal Roger Mahony of the Los Angeles archdiocese, an outspoken champion of immigrant rights, has lobbied against a walkout. "Go to work, go to school, and then join thousands of us at a major rally afterward," Mahony said. And Los Angeles Mayor Antonio Villaraigosa, who has long fought for immigrant rights, has said he expects protesters to be "lawful and respectful" and children to stay in school. In Washington on Thursday, immigrant-rights activists brushed off talk of a backlash. "This is going to be really big. We're going to have millions of people," said Juan Jose Gutierrez, director of the Latino Movement USA. "We are not concerned at all. We believe it's possible for Congress to get the message that the time to act is now." (Additional reporting by Aarthi Sivaraman in Los Angeles, Dan Trotta in New York and Michael Conlon in Chicago) Isn't this nice! now the illegals are attempting to guide congress! our country is filling up with criminals like these and our elected leaders stand by and do nothing! pick up the phone and make a few calls folks, it cant hurt and it might make a difference. if we stand by and do nothing, soon that's all we will have to do! kiss your job goodbye to the illegals!