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A national Quaker organization is holding a vigil Monday night and kicking off 40 days of fasting and prayer in Colorado to keep up the pressure on Congress to overhaul the U.S. immigration system.

In California, labor and civil rights groups and community leaders are holding roundtables around the state to discuss the impact of immigration reform on the economy and plan strategies for pushing Congress to take action on improving the system.

On Sunday, dozens of Catholic pastors across the country focused their masses on immigration, and urged their congregants to contact their lawmakers and press for them – particular members of the House of Representatives – to bring a reform bill to a vote soon.

With members of Congress back from summer recess, and the Syrian crisis eclipsing most other issues, those pushing for an immigration reform measure to pass this year are giving their effort a final strong push.

Advocates are worried about the talk among many members of Congress about how the odds are increasingly stacked against passage of an immigration reform bill – not just because of Syria, but because of the few legislative days left for the year.

The talks mark quite a change from earlier this year, when – with Latino voters said to have been fed up over some in the GOP taking a hard line on immigration, and President Obama vowing to make it a priority in his second term – a sweeping reform bill seemed to be nearing a reality.

“These actions will show support for our neighbors and co-workers who are facing firsthand the devastating consequences of federal inaction on comprehensive immigration reform, two-thirds of whom have been here more than 10 years,” said a statement released by the Quaker organization, American Friends Service Committee, explaining the objective of the vigil and 40-day fast.

The group said it would also pray for “courageous leadership in Washington to act now on immigration reform.”

Of particular urgency to advocates of a more lenient immigration system is a reform bill that would provide a pathway to legalization for many of the estimated 11 million undocumented immigrants living in the United States.

A bipartisan measure that passed in the Senate in late June included such a provision, as well as enhanced border security, expanded visas for high-tech and agricultural workers, and mandatory participation for employers in a federal system that would determine a prospective employee’s eligibility to work in this country.

Many advocates are concerned that immigration reform – which is now in the House of Representatives – will just be left to die by conservative Republicans who firmly oppose a pathway to legalization for undocumented immigrants. Republicans have a majority in the House.

“What are House leaders afraid of?” Frank Sharry, executive director of America’s Voice, said in a statement. “As August recess demonstrated, the anti-immigrant movement has no juice and the pro-reform movement is on fire. The House leaders know what’s at stake:  If they block reform, the GOP will lose seats in 2014 and lose the White House in 2016.”

Even before the revelation that the Syrian government appeared to be behind an Aug. 21 chemical weapons attack on its people that left nearly 1,500 dead, momentum in Congress to overhaul the immigration system had slowed to a crawl.

Shortly after the Senate passed the immigration reform bill, House Republicans vowed not to rubber-stamp the Senate version, and said they instead would adopt a separate, piecemeal approach with various bills instead of an all-encompassing one.

Moreover, lawmakers are facing other divisive issues on the agenda – the debt ceiling and the budget, what to do about funding for Obama’s controversial Affordable Care Act, and the Voting Rights Act, parts of which were dropped by the U.S. Supreme Court.

Last week, Rep. Luis Gutierrez, an Illinois Democrat who is one of Congress’ most vocal proponents of a pathway to legal status for undocumented immigrants, spoke of protests that will be held nationwide on Oct. 5 to keep the issue on the congressional radar.

"October 5 is the start of concerted action in the country to keep alive the hope of an immigration reform,” Gutierrez said. “We will not accept that Congress doesn't approve the immigration reform.”

The protests are planned for 60 cities and are expected to include religious, labor and civil rights groups, according to published reports.

Conservative taxpayer groups who typically fund GOP primary challenges have remained largely silent on immigration. Anti-immigration activists have failed to organize large-scale demonstrations or generate the kind of public backlash that killed Congress' last attempt to remake immigration policy, in 2007.

Many House Republicans come from swing districts with sizable Hispanic populations that could make a difference in next year's elections, tipping the balance of power in the GOP-controlled House. The lawmakers also feel the pressure from business interests that rely on immigrant labor.

"Congress people who may have been on the fence are realizing it's safe to get in the water," said Ana Navarro, a GOP strategist who led Hispanic outreach for Sen. John McCain's presidential campaign in 2008. "There is safety in numbers."

The Associated Press contributed to this story.

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