President Barack Obama on Friday announced a major election-year immigration policy shift to halt the deportation of certain younger illegal immigrants and grant them work permits, infuriating Republicans with what the president said is a step toward making the country’s immigration system “more fair, more efficient and more just.”

In a speech from the Rose Garden, Obama explained that the new policy would spare young people who are “Americans in their heart” the fear of deportation.

“These are young people who studied in our schools. They play in our neighborhoods, they’re friends with our kids, they pledge allegiance to our flag. They’re Americans in their heart, in their minds, in every single way but one — on paper,” the president said. “They were brought to this country by their parents, sometimes even as infants, and often have no idea that they’re undocumented until they apply for a job or a driver’s license or a college scholarship.”

The new rule, which bypasses Congress and is effective immediately, could affect hundreds of thousands of people who are in the country without legal papers.

In his speech, Obama also blasted Republicans for blocking the passage of the DREAM Act, which would give some illegal immigrants a path to citizenship. The rule will apply to those under 30 who were brought to the U.S. before the age of 16 and are considered to present no risk to national security or public safety.

“I’ve said time and time again to Congress: send me the DREAM Act, put it on my desk, and I will sign it right away,” he said. “Both parties wrote this legislation a year and a half ago, Democrats passed the DREAM Act in the House but Republicans walked away from it. It got 55 votes in the senate but Republicans blocked it.”

The president, who was visibly irritated when the Daily Caller’s Neil Munro interrupted his remarks, emphasized that he would not give up on achieving comprehensive immigration reform during his presidency.

“As long as I’m president, I will not give up on this issue, not only because it’s the right thing to do for our economy … not just because it’s the right thing to do for our security, but because it’s the right thing to do period,” he said.

The Department of Homeland Security announced the new policy Friday morning, drawing reactions from outraged Republicans even before the president’s speech. Conservative lawmakers were quick to accuse the president of overstepping his authority by making a major immigration shift without congressional approval.

Iowa Rep. Steve King, for example, said Obama is “planning to usurp the constitutional authority of the United States Congress” and for giving “amnesty by edict” to illegal immigrants. King said Congress voted against the DREAM Act and that it is unacceptable for the president to move forward with the policy shift anyway. He even warned on Mike Huckabee’s radio show that he is prepared to sue the administration.

Other Republicans, including Reps. Allen West and Peter King and Sen. Chuck Grassley, also expressed their disappointment. Grassley charged that the president is putting “election-year politics above responsible policies.”

Meanwhile, Sen. Marco Rubio — whose parents are Cuban immigrants — said the new rule threatens the goal of reducing the number of illegal immigrants but did acknowledge that it would provide at least a short-term sense of relief to some illegal immigrants.

“Today’s announcement will be welcome news for many of these kids desperate for an answer, but it is a short-term answer to a long-term problem,” the Florida Republican said. “And by once again ignoring the Constitution and going around Congress, this short-term policy will make it harder to find a balanced and responsible long-term one.”

The action further refines the administration’s announcement last summer that it would undertake a review of the cases of some 300,000 illegal immigrants who were facing deportations, and allow some of those determined to have no criminal record to stay in the country. The change does not, however, offer eligible individuals a path to citizenship.

“Our nation’s immigration laws must be enforced in a firm and sensible manner,” Homeland Security Secretary Janet Napolitano said. “But they are not designed to be blindly enforced without consideration given to the individual circumstances of each case. Nor are they designed to remove productive young people to countries where they may not have lived or even speak the language. Discretion, which is used in so many other areas, is especially justified here.”

The application process will begin within two months, DHS said. The change could affect as many as 800,000 immigrants, according to The Associated Press. To be eligible, one must have lived in the U.S. for at least five years and have a clean criminal record. The individual must also currently be in school, have graduated from high school or were honorably discharged from the Coast Guard or Armed Forces.

The new policy comes just months before the general election, when the Latino vote is expected to play an important role. Hispanic leaders have called on Obama to do more to change the country’s deportation policies with Congress filing to pass the so-called DREAM Act.