A push to bring immigration legislation to the House floor, led by an unusual coalition of business executives, prominent conservatives and evangelical leaders, threatens to create another schism in the Republican Party and could have a noticeable effect on campaign contributions before the midterm elections.
Several Republican executives and donors who are part of a lobbying blitz coming to Capitol Hill next week said they were considering withholding, or had already decided to withhold, future financial support to Republican lawmakers they believe are obstructing progress on immigration.
"I respect people's views and concerns about the fact that we have a situation in the United States where we have millions of undocumented immigrants, said Justin Sayfie, a lawyer from Florida who said he helped Mitt Romney raise more than $100,000 for his presidential campaign last year, in addition to helping other Republican candidates. "But we have what we have. This is October 2013. And the country will be better off if we fix it.
Capitol Hill has for months been the focus of immigration advocates urging lawmakers to take up one of the four measures that have been approved by the Republican-led House Judiciary Committee. What is different about next week's lobbying effort is that it will include about 600 mostly conservative leaders in business, agriculture and religion who will focus on 80 representatives from 40 states ' all of them Republican.
The effort comes just weeks after House conservatives alienated many longtime supporters, including much of corporate America, by trying to block financing for Mr. Obama's health care law, a move widely blamed for the government shutdown. The intraparty tension that was apparent in the budget standoff could resurface in the immigration fight, though the sides may not align in exactly the same way.
Sponsors of next week's event include the U.S. Chamber of Commerce; the National Immigration Forum; FWD.us, a political action group set up by Silicon Valley executives including Mark Zuckerberg, the founder of Facebook; and the Partnership for a New American Economy, which is led jointly by Mayor Michael R. Bloomberg of New York, Rupert Murdoch and Bill Marriott Jr.
Pushing back against the pressure to act from within their own party, a core group of conservatives said in interviews this week that they would not be intimidated by corporate America or other outside parties, even though in this case that includes farmers, evangelical leaders and some prominent conservatives.
"I care about the sovereignty of the United States of America and what it stands for, and not an open-door policy, said Representative Ted Yoho, Republican of Florida, who is one of several conservatives opposing all of the bills the House is currently considering.
Though House Republican leaders ' including Speaker John A. Boehner of Ohio and Representative Eric Cantor of Virginia, the majority leader ' have expressed support for moving on their own immigration measure this year, given that the Senate has already passed a comprehensive bill, the prospect for any legislation before year's end is uncertain.
There is intense division within the party over the proposals under consideration, and some hard-line conservative members have made it clear that they have no interest in advancing a key part of Mr. Obama's agenda.
Even some who support a measure to increase border security say they would not vote for such a bill, fearing that it could become a vehicle to grant citizenship to an estimated 11 million immigrants in the United States illegally.
"We have seen the character of this president, and the way that he does business, said Representative Steve King, Republican of Iowa, explaining why he would oppose any measure.
Looking to restart discussion on immigration after months when it was overshadowed by foreign policy crises and the budget dispute, Mr. Obama spoke at the White House on Thursday and said Democrats and Republicans in the House must unite to pass an immigration package.
"Everybody wins here if we work together to get this done, the president said.