(recasts lead, updates with release of Republican principles, reaction)
By Richard Cowan and Susan Cornwell
CAMBRIDGE, Md., Jan 30 (Reuters) - Republican leaders in the U.S. House of Representatives on Thursday took their first step toward reforming an outdated immigration system as they floated a series of principles intended to guide a possible legislative effort this year.
According to a draft document obtained by Reuters that was intended to gauge support among the House's 232 Republicans for tackling immigration reform this year, some children who were brought illegally into the United States by their parents would be granted citizenship.
Meanwhile, some of the millions of adult undocumented residents would no longer have to worry about being deported and would be allowed to work in the United States if they cleared a series of hurdles.
Significantly, however, they would not win a pathway to citizenship that Democrats and immigration reform groups so badly want.
The move, spearheaded by House Speaker John Boehner, marked a significant shift within the Republican Party, whose members previously supported deporting the more than 11 million people who are living in the United States illegally.
The immigration reform ideas were being discussed in closed-door sessions House Republicans were holding this week at a resort on the eastern shore of the Chesapeake Bay in Maryland, about 85 miles outside Washington, D.C.
A congressional aide told Reuters that the initiative was sparking a heated discussion among House Republicans, some of whom strongly disagreed with the principles.
This set of ideas has a long way to go before being translated into actual legislation that could be debated on the House floor as an alternative to a bipartisan bill that passed the Democratic-controlled Senate last June. And there were no guarantees that it would even advance that far.
Reactions were varied to the broad principles House Republican leaders laid out in a one-page document.
AFL-CIO President Richard Trumka, speaking for the largest U.S. labor organization, blasted it as "a flimsy document that only serves to underscore the callous attitude Republicans have toward our nation's immigrants."
Trumka said that the establishment of a pathway to citizenship for the 11 million, which the House initiative denies except for children, was needed for any immigration bill that is enacted.
Another view came from a spokesman for the conservative group Heritage Action, Dan Holler, who said the language amounted to "amnesty" for some illegal immigrants.
Some prominent Democrats in Congress held out hope that Boehner has produced a catalyst for a deal.
"While these standards are certainly not everything we would agree with, they leave a real possibility that Democrats and Republicans, in both the House and Senate, can in some way come together and pass immigration reform," said Senator Charles Schumer of New York, who was a main sponsor of the Senate-passed bill.
Meanwhile, Representative Luis Gutierrez of Illinois, a Democrat and an outspoken proponent of immigration reform, said in a statement that the most important priority now was to "stop the massive increase in deportations." He said he would await detailed legislation from Republicans before knowing whether he could support it.
Before any illegal immigrants could obtain legal status or citizenship, further steps would have to be taken to secure the southwestern U.S. border and to clamp down on undocumented workers already in the country, according to the document.
One House source said that the principles being floated could be changed, depending on how rank-and-file House Republicans react.
RALLYING AROUND AN OBAMACARE ALTERNATIVE
Early indications were that House Republicans were coalescing around advancing new healthcare legislation that they will present as an alternative to "Obamacare," which suffered a troubled rollout in October.
As with immigration reform, Republicans presented a general set of healthcare principles that they said would "inform" the effort -- along with bills already introduced.
They emphasized affordability, access to care, and a choice of private options and doctors, but offered no specifics about how these goals would be accomplished.
But such consensus was not apparent on immigration reform. Some outspoken conservative Republicans pointedly disagreed with Boehner's desire to move forward on legislation.
"It's not just the conservatives. I think a majority of the conference" feel that now is "not the time to deal with the issue," Representative Raul Labrador of Idaho told Reuters in a telephone interview.
Labrador, who last year was part of a bipartisan group of lawmakers working on a comprehensive immigration deal, said some Republicans fear that getting bogged down in a contentious immigration debate this year could jeopardize the party's "great opportunity" to take control of the Senate away from Democrats in the November congressional elections.
Even allies of Boehner such as Representative Greg Walden of Oregon said that the first half of 2014 could go by without any action on the contentious immigration issue. "It's probably months out, I don't know," Walden said on the sidelines of the Republican conference. (Additional reporting by David Lawder; Editing by David Storey, Mohammad Zargham and Andrew Hay)