WASHINGTON — The Obama administration will stop deporting young illegal immigrants who come to the United States as children, a move that President Obama said was "the right thing to do" on immigration policy and one likely to push the battle for Latino voters to the forefront of the presidential campaign.

The announcement was touted by the president and his allies as a major step toward a more humane deportation policy. It will take effect immediately.

Immigration activists long have pressured Obama to act to protect young immigrants who were brought to this country illegally by their parents and are forced to live in the shadows or face deportation.

Obama announced the decision in the White House Rose Garden, seizing the news cycle on a slow Friday one week before he is scheduled to address a group of Latino officials in Orlando, Fla.

"These are young people who study in our schools, they play in our neighborhoods, they're friends with our kids, they pledge allegiance to our flag. They are Americans in their heart, in their minds, in every single way but one: on paper," said the president, interrupted frequently by one reporter's shouted questions.

Range of GOP reactions

Some Republicans attacked the move as an election-year political ploy and/or questioned the constitutionality of the move.

House Judiciary Committee Chairman Lamar Smith, a Texas Republican known for frequent calls for tougher immigration laws, denounced the administration's decision as "amnesty."

"It also blatantly ignores the rule of law that is the foundation of our democracy," Smith said in a statement. "This huge policy shift has horrible consequences for unemployed Americans looking for jobs and violates President Obama's oath to uphold the laws of this land."

Other Republicans, including much of the congressional leadership, were silent as they weighed the political consequences. The GOP base in recent years has become opposed to policies viewed as lenient, but some lawmakers recognize that hard-line rhetoric threatens to alienate a generation of Latino voters, the fastest-growing demographic in the electorate.

GOP presidential rival Mitt Romney, facing his own pressure over how to handle immigration issues after playing to the anti-immigration faction of his party during the primaries, waited hours before making a statement, eventually saying that "we have to find a long-term solution" to the country's immigration problems, "but the president's action makes reaching a long-term solution more difficult."

Florida Sen. Marco Rubio, a Cuban American often mentioned as a potential Romney vice-presidential candidate, has been among Republicans who have called for a more practical approach to illegal immigration. Still, he criticized Obama's decision as a bandage that won't mend the problem, while suggesting the president's move was unconstitutional.

"There is broad support for the idea that we should figure out a way to help kids who are undocumented through no fault of their own, but there is also broad consensus that it should be done in a way that does not encourage illegal immigration in the future," Rubio said in a statement. "This is a difficult balance to strike, one that this new policy, imposed by executive order, will make harder to achieve in the long run."

How it will work

Contrary to one of Rubio's assertions, Obama technically did not issue an executive order. Rather, the deportation policy was itemized in a three-page memo issued by Homeland Security Secretary Janet Napolitano.

Citing the department's "prosecutorial discretion," the memo specifies the population of illegal immigrants that essentially will be protected from deportation: those younger than 30, who were 15 or younger when they entered the United States and who are students, high-school graduates or veterans.

Individuals also must meet numerous other requirements to be eligible to apply.

They must have resided in the country continuously for at least five years and must be present now. Felons, immigrants convicted of violent crimes, those convicted of a significant misdemeanor or more than one misdemeanor, repeat offenders of immigration law, and those who for some other reason pose a security or safety threat are disqualified.

Immigrants who meet those requirements will be allowed to apply for work permits and will be granted deferred action on deportation for two years. That status will be renewable, one official said.

"Not a permanent fix"

Obama emphasized that the decision was a temporary measure.

"This is not amnesty. This is not immunity. This is not a path to citizenship. It's not a permanent fix," he said. "This is the right thing to do."

The protected population is similar to that covered by the so-called DREAM Act, legislation that has failed to pass Congress since 2001. Obama's action, though, does not go as far as the legislation.

"It is not a right to stay indefinitely; it would not grant benefits generally associated with visas (and) it would not allow students to enter or leave the country with authorization," Raquel Aldana, a professor at the University of the Pacific McGeorge School of Law, noted in an email. "It could go away the moment a new administration comes in or the moment this administration decides to end it."

As for constitutional concerns, the executive branch's authority to defer deportation, as an act of prosecutorial discretion, is not spelled out explicitly either in regulations or in statutory law. The Immigration and Nationality Act, however, gives the Department of Homeland Security the general authority to enforce immigration laws. Federal courts, moreover, have recognized that officials can exercise discretion in determining deportation priorities.

Aldana said this use of prosecutorial discretion could be the largest-ever application of such "deferred action," if estimates that upward of 800,000 illegal immigrants may benefit are correct.

Scholarly skeptics of the administration's decision can question whether shielding such a large population is an appropriate use of a policy that courts have said exists for the "administrative convenience" of an agency juggling priorities amid limited resources.