In Dallas Sunday, tens of thousands banged drums, waved U.S. flags and shouted "Si Se Puede!", Spanish for "Yes, we can!" - a slogan often used by the late Farmworkers Union founder Cesar Chavez - as they urged Congress to pass legislation to help an estimated 11 million undocumented workers.
The demonstrators in Texas included business owner Michael Longcrier, who carried a sign that read "We work because of the hard working immigrants that work."
"I have friends in this march. I have friends that make my business work," said Longcrier.
Similar sentiments were expressed by demonstrators Sunday in New Mexico, Minnesota, Michigan, Iowa, Alabama, Utah, Oregon, Idaho and California.
"If we don't protest, they'll never hear us," said Oscar Cruz, 23, a construction worker who marched among the estimated 50,000 in San Diego. Cruz, who came illegally to the U.S. in 2003, said he had feared a crackdown but felt emboldened by the large marches across the country in recent weeks.
Some protesters wore shirts that said "No HR 4437," referring to the House bill passed in December that would build more walls along the U.S.-Mexico border, make criminals of people who helped undocumented immigrants and make it a felony, rather than a civil infraction, to be in the country illegally.
In Birmingham, Ala., demonstrators marched along the same streets where civil rights activists clashed with police during the 1960s and rallied at a park where a statue of Martin Luther King Jr. stands as a reminder of the fight for equal rights and the violence that once plagued the city.
"We've got to get back in touch with the Statue of Liberty," said The Rev. Lawton Higgs, a United Methodist pastor and activist. "We've got to get back in touch with the civil rights movement, because that's what this is about."
In some places, the rallies also drew counter-demonstrators.
In Salt Lake City, Jerry Owens, 59, a Navy veteran from Midway wearing a blue Minuteman T-shirt and camouflage pants, held a yellow "Don't Tread on Me" flag.
"I think it's real sad because these people are really saying it's OK to be illegal aliens," Owens said. "What Americans are saying is 'Yes, come here. But come here legally.' And I think that's the big problem."
The chairman of the Senate Judiciary Committee has expressed optimism that senators will reach a compromise on an immigration reform bill when they return from their spring vacation.
"I think tempers will cool over a two-week period," said Sen. Arlen Specter, R-Pa. "And also, there are going to be some expressions by many people very unhappy with the Senate not passing a bill and very unhappy with the House bill" that would make being an illegal immigrant a felony.
"There's a real risk of significant political fallout here, and members of the Senate think about that, believe it or not," Specter said on "Fox News Sunday."
The political future of the immigration bill is still very much in doubt. Last week, afell apart amid partisan bickering over amendments to the legislation.
Specter on Sunday pledged to have legislation ready for debate soon after lawmakers return from their two-week recess.
Even if another compromise can be found in the Senate, some Republicans in the House are indicating that it won't make through their part of Congress. They disagree with Senate provisions that, if passed, would pave the way for eventual legal status for millions of illegal immigrants in the United States.
As for any bill that offers a guest worker program – which Tancredo terms as "amnesty" for illegal immigrants – the Colorado congressman said, "It sends a terrible message to every single person who has ever come in this country the right way."
House Majority Leader John Boehner, R-Ohio, said the debate needed to be narrowed. "Until we begin to secure our borders and enforce our immigration laws, I don't think we ought to be talking about a more comprehensive approach," Boehner said on ABC's "This Week."
In his weekly radio address, President Bush Saturday said the deal fell apart when Minority Leader Harry Reidon more than three Republican-backed amendments.
"I call on the Senate Minority Leader to end his blocking tactics and allow the Senate to do its work and pass a fair, effective immigration reform bill," the president said.
Reid shot back that Mr. Bush and Senate Majority Leader Bill Frist "are flat-out wrong about what happened to the immigration bill," saying Democrats proved their commitment to a comprehensive, bipartisan measure by voting twice in favor of it.
"It was President Bush and Republicans in Congress who lacked the backbone to stand up to the extreme right wing of their party, filibustered reform twice in two days, and put partisan politics ahead of border security and immigration reform," Reid said.
Sen. John Cornyn of Texas and other opponents have expressed frustration that they were unable to gain votes on proposals to toughen enforcement or to leave immigration policy unchanged until the border had been made secure.
The bill would have provided for stronger border security, regulated the future entry of foreign workers and created a complex set of regulations for the estimated 11 million immigrants illegally in the United States.
Rep. Peter King, chairman of the House Homeland Security Committee, said he would have trouble with provisions providing legal status for illegal immigrants already here. He called the Senate plan a "bureaucracy of rubber stamps" that rewards people who break the law.
"With the intelligence reports we have of terrorists trying to be smuggled into the country ... we cannot be doing anything which is going to encourage more illegals to come into the country," said King, R-N.Y., who appeared with Specter on Fox News.
"The Senate, I think, was, quite frankly, intimidated by having hundreds of thousands of people in the streets waving flags," said King, "but I don't think we should pass legislation or devise legislation based on how many people you can get out into the street."