President Obama’s surprise decision last summer to use executive authority to halt the deportation of some immigrants who were brought to the country illegally as children won raves from advocates stung by the defeat of similar legislative proposals in Congress.

Since then, the administration has granted more than 400,000 of those young immigrants temporary waivers to live and work in the United States, making Deferred Action for Childhood Arrivals one of largest legalization efforts in decades.

The popularity of the program has helped persuade leading House Republicans to consider backing legislation that would offer permanent legal status to the same set of 1.7 million undocumented immigrants.

GOP supporters say such a measure could help break a deadlock on Capitol Hill over comprehensive immigration reform. But many advocates who once fought for the failed Dream Act, which would have provided the children a chance at citizenship, now say they will no longer be satisfied with legislation that does not include the vast majority of the 11 million immigrants living in the country illegally. Many worry that Republicans will pass a legalization program for children of illegal immigrants and use it as an excuse to kill broader reform efforts.

“We will not allow lawmakers to condemn our parents to second-class status,” Cristina Jimenez, managing director of United We Dream, a youth organization, said late last month. “Our parents’ dreams enabled our dreams, and we owe our success to them and the sacrifices they made.”

With Congress on summer recess until next month, the key question when lawmakers return remains how far House Republicans are willing to go to compromise with the Senate, which has approved a comprehensive plan that includes a 13-year path to citizenship for most illegal immigrants.

Advocates have long put a priority on gaining legal status for the children of illegal immigrants, arguing that most did not choose to enter the country illegally and have spent the majority of their lives here.

House Majority Leader Eric Cantor (R-Va.) and Judiciary Committee Chairman Bob Goodlatte (R-Va.) echoed that rationale in announcing that they are developing legislation, called the Kids Act, that would offer legal status for younger immigrants. Both lawmakers voted against the Dream Act.

“These children came here through no fault of their own and many of them know no other home than the United States,” Goodlatte said in a recent statement.

Longtime immigration supporters say that’s no longer enough, arguing that the political calculus changed after Obama was reelected with overwhelming Latino and Asian support. Last month, United We Dream held a demonstration at the Capitol opposing the Kids Act before a House subcommittee hearing on immigration.

“In 2010, they would have welcomed this, but that was before Republicans defeated the Dream Act, before the president granted [deportation] relief and before the 2012 election,” said Frank Sharry, executive director of America’s Voice, an immigration advocacy organization. Republicans “have come out of the Stone Age and are now in the Middle Ages. Hopefully by the end of the year, they’ll be in the 21st century.”

The Obama administration, too, is rejecting the idea of a Dream Act-style proposal, even as officials tout the president’s deferred-deportation program as a qualified success after its first year.

Under the program, applicants must have been brought to the United States before they were 16 and must have resided in the country continuously since June 2007. Once approved, they are eligible to apply for a Social Security number, a federal work permit and, in most states, a driver’s license. They are allowed to remain in the country for two years before they must reapply.

The vast majority of applicants have been approved, according to statistics provided by U.S. Citizenship and Immigration Services.

Asked whether the administration’s program is similar to what Republicans are considering for the Kids Act, White House press secretary Jay Carney said Obama’s executive action was never intended to be a substitute for broader changes to immigration laws.

“The long-term problem has to be addressed through comprehensive immigration reform,” Carney said. “Everyone on Capitol Hill knows that, including Republicans in the House who have yet to stake out a position on this.”

Obama authorized the deportation-waiver program last summer after being presented with the plan by Homeland Security Secretary Janet Napolitano, who was seeking ways to reduce the caseloads of customs and border-control agents so they could focus on immigrants who had committed multiple crimes.

Although some Obama advisers thought the move was politically risky, it put pressure on Republican presidential nominee Mitt Romney, who struggled to win support from Latinos and Asians after endorsing the concept of “self-deportation” for illegal immigrants.

In the year since its implementation, however, the program has revealed the limits of Obama’s executive authority.

The number of immigrants who have been granted two-year deportation waivers is less than half of the 950,000 who are estimated to be eligible. (An additional 770,000 could become eligible in coming years, according to an analysis by the Pew Hispanic Center.)

Hundreds of thousands have not applied for the legal protections, and the number of applicants has dwindled rapidly since last year, according to the Citizenship and Immigration Services statistics. More than 116,000 people applied in October 2012, compared with about 18,000 this June.

Advocates said the biggest barriers are the $465 application fee and fears among immigrants of being deported or jailed if they come forward. Some potential applicants have decided to wait until Congress resolves the immigration debate, hoping they can pursue full citizenship instead, advocates said.

In Arizona and Nebraska, meanwhile, Republican governors have decreed that those who receive deportation waivers are not eligible for driver’s licenses, even if they have federal work permits. The ACLU and advocacy groups have brought lawsuits to try to overturn the rulings, arguing that the immigrants often need to drive to get to their jobs.

“One of things that immigration reform has to address is to make crystal clear that states cannot make distinctions among immigration statuses,” said Kamal Essaheb, a lawyer with the National Immigration Law Center. “Part of making implementation go smoothly is making sure states with governors or legislators who are opposed to reform do not have the opportunity to undermine it.”

As the immigration debate drags on in Congress, advocates have pressured the White House to expand the program to cover more of the immigrants living in the country illegally. But so far the president has rebuffed them, citing the administration’s focus on passing a broader reform bill.

“We have to enforce the law, including, obviously, deporting criminals and others, and that’s what we’re doing,” Carney said. “We need to address this in a comprehensive way.”