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President Barack Obama makes remarks about the Department of Homeland Security's recent announcement about deportation of illegal immigrants in the Rose Garden at the White House June 15, 2012 in Washington, D.C.

Updated 4:18 p.m. ET - The Obama administration announced on Friday that it would no longer seek the deportation of most young illegal immigrants, and would instead allow them to apply for work permits, a significant policy shift with potentially major electoral implications.

The Department of Homeland Security said that, effective immediately, the government would no longer seek the deportation of illegal immigrants who were brought to the United States as children, and would allow them to apply for work permits if they meet certain criteria.

The decision was intended to make America's immigration system "more fair, more efficient and more just," President Barack Obama said in an afternoon statement in the Rose Garden.

"They were brought to this country by their parents, sometimes even as infants, and oftentimes had no idea they were undocumented until they applied for a job," the president said. "They are Americans in their hearts, in their minds ... in every single way but one: on paper."

A senior administration official said in a conference call with reporters that as many as 800,000 undocumented immigrants stand to benefit from this change.

Homeland Security Secretary Janet Napolitano said that the shift represented neither immunity nor amnesty -- buzzwords for conservatives who oppose illegal immigration -- but instead represented an instance of "prosecutorial discretion" in which the government had re-evaluated its priorities in enforcing the law.

"This is not amnesty; this is not immunity; this is not a path to citizenship," Obama said, calling today's move a "temporary fix."

Obama interrupted by heckling at immigration announcement

The shift essentially accomplishes many of the legislative intentions of the DREAM Act, an immigration reform bill that had stalled in Congress due to Republican objections. President Barack Obama favors the legislation, while presumptive Republican presidential nominee Mitt Romney has said he would veto that law.

The new rule comes amid a bruising election year fight between Obama and Romney, in which the Latino vote could be decisive. Obama enjoys a strong advantage with Latino voters, winning 61 percent of Latinos vs. 27 percent for Romney in a mid-May NBC News/Wall Street Journal/Telemundo poll.

Romney, speaking to reporters in New Hampshire, said he thought that the status of children who were brought to the United States illegally is important to resolve, but only on a long-term basis.

"I think the action that the president took today makes it more difficult to reach that long term solution because an executive order is, of course, just a short term matter. It can be reversed by subsequent presidents," Romney said. He didn't say whether he would seek the new rule's reversal.

"If I'm president, we'll do our very best to have that kind of long term solution that provides certainty and clarity for the people who come into this country through no fault of their own by virtue of the actions of their parents," the former Massachusetts governor added.

The Hispanic vote is of particular importance in swing states like Nevada, Colorado, New Mexico and Florida, among others. Those states could swing the election toward Obama or Romney, elevating the importance of the margin between the two candidates with Latino voters.

Alex Wong / Getty Images

Immigration activists gather in front of the White House to celebrate the Obama Administration's announcement about deportation of illegal immigrants June 15, 2012 in Washington, D.C.

Obama's biggest challenge, though, has involved motivating Latino voters to turn out for him with the same strength they had in 2008. The president had faced lingering complaints stemming from his inability to advance the comprehensive immigration reform he had promised as a candidate in 2008.

Skepticism, joy among illegal immigrants over Obama decision

The president tweaked Republicans in Congress for blocking the legislation, saying that he continued to favor both the full DREAM Act as well as a broader comprehensive immigration reform package that would allow a pathway to citizenship.

"There's no reason that we can't come together and get this done. And as long as I'm president, I will not give up on this issue," Obama said.

In a memorandum to immigration enforcement officials, Napolitano wrote that immigrants who were illegally brought to the United States as children "lacked the intent to violate the law," and pose few national security risks.

The memo said the government would not pursue immigrants who met five criteria. Individuals must:

• Have come to the United States under the age of 16,
• Be no older than 30,
• Be currently enrolled in school, have graduated high school or served in the military,
• Have been in the country for five continuous years, and
• Have a clean criminal record.

A senior administration official noted that the new rules were not permanent, though, and conceded that a different administration with a different policy could conceivably choose to withdraw this regulation.

"The executive can always change its mind about how to exercise discretion," said the official.

The policy shift presents a challenge for Romney, who ran to the right of some of his opponents on the issue of immigration during the Republican primary. He had opposed the DREAM Act, and explained during a debate that his immigration policy involved "self-deportation."

First Read: Obama leads big with Latinos

That hard-line stance prompted handwringing among Republicans who have long worried about the long-term political fallout associated with alienating Latino voters. Florda Gov. Jeb Bush suggested earlier this week that much of the Republican rhetoric surrounding immigration had been "insulting."

"Change the tone would be the first thing," he said of his advice to Republicans. "Second, on immigration, I think we need to have a broader approach."

Ironically, the Obama administration's new rule would accomplish many of the same goals of a limited version of the DREAM Act proposed by Florida Republican Sen. Marco Rubio, which stops short of offering young illegal immigrants citizenship, but gives them a type of legal status. Romney said he was considering the proposal from Rubio, a popular choice of conservatives to round out the Republican ticket as a vice presidential nominee.

In a statement, Rubio straddled praise and criticism for the move.

"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," he 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."

Romney said of Rubio: "I'd like to see legislation that deals with this issue and I happen to agree with Marco Rubio as he considers this issue. He said that this is an important matter, we have to find a long term solution but the president's action makes reaching a long term solution more difficult."

Ross D. Franklin / AP

Rep. Gabrielle Giffords and Ron Barber celebrate early Tuesday.

Updated at 12:54 a.m. ET: Democrat Ron Barber has won a special House election in southern Arizona to finish the term of former Rep. Gabrielle Giffords, The Associated Press projected.

Giffords, who was critically injured in a Jan. 2011 event in her district, resigned earlier this year.

A former aide to Giffords, Barber, who was also injured in the attack outside a supermarket that left six dead and 12 others injured, faced a challenge from Jesse Kelly, a Republican who narrowly lost to Giffords in the 2010 midterm elections.

The campaign was imbued with emotions that still linger from the attack, which forced Giffords’s retirement – despite remarkable progress toward recovery – earlier this year. But the special election campaign has also assumed a degree of political significance, given each party’s aggressive efforts to win the seat.

Bruising battle
The race evolved into a bruising battle between Kelly and Barber, fueled by hundreds of thousands of dollars of outside spending in the campaign. The district will be redrawn for this fall’s election, slightly in Democrats’ favor. But Giffords first won accolades for her political resiliency in a district that Republicans have won in the previous three presidential elections.

Democrats focused their resources on painting Kelly as an extremist who would seek radical changes to Medicare and Social Security even well beyond what most House Republicans had voted for in Wisconsin Rep. Paul Ryan’s budgets the past two years.

House Majority PAC, a Democratic super PAC, released one particularly effective ad featuring video of Kelly talking about eliminating corporate taxes and calling Social Security and Medicare Ponzi schemes.

Giffords herself made several public appearances in the past week – along with her husband, former astronaut Mark Kelly – pushing for her onetime aide.

A loss for Democrats would have threatened another demoralizing loss, though, on the heels of Republicans Gov. Scott Walker’s survival of a recall campaign last week in Wisconsin.

Both sides will inevitably spin the results of Tuesday’s primary as a harbinger for their chances come November, though the ultimate takeaways from this race might actually be more limited.

Testing ground for attacks
Democrats’ path toward retaking the majority in the House never ran through this seat, which they had controlled since Giffords first won in 2008. Barber will have to stand for re-election in November, and Republicans – including Kelly – vow to contest that race, too. But the district will favor Democrats more slightly, and it’s not clear how inclined that national Republicans will feel to invest heavily in that campaign.

But the race against Kelly provided Democrats in Washington a testing ground for their attacks against Republicans this fall associated with Medicare and Social Security.

Additionally, Republicans gained traction versus Barber by trying to tie him to House Minority Leader Nancy Pelosi and President Obama.

Barber had hedged for a period on whether he would support Pelosi as Democrats’ leader as elected, and he similarly punted on a May question about whether he would even vote for Obama. (Barber later clarified that he intended to vote for the president in November.)

But the fact that a Democratic candidate would feel the need to distance himself from Obama in Arizona raises questions about the viability of the president’s effort to win that state this fall. The Obama campaign has included Arizona in several of its Electoral College roadmaps; the state is rated Lean Republican in NBC News’ battleground map.

The Associated Press contributed to this report.

Updated 4:50 p.m. ET- President Barack Obama endorsed the right of same-sex couples to marry on Wednesday, a landmark pronouncement made in light of mounting pressure from gay rights advocates.

Obama became the first U.S. president to back the right of gay and lesbian couples to marry, a reversal from views expressed during the 2008 campaign, when he said he opposed same-sex marriage but favored civil unions as an alternative.

Related: The ‘evolution’ of Obama’s stance on gay marriage

Obama told ABC News that, after reflection, he had "concluded that for me personally it is important for me to go ahead and affirm that I think same-sex couples should be able to get married."

Related: Romney calls marriage 'tender' issue, skirts Obama remarks

In making his announcement, Obama completes what he had described as an “evolution” in his views on this issue, hastened by growing fervor this week involving gay rights. The growing pressure was capped Tuesday by North Carolina voters’ approval of a constitutional amendment banning not only same-sex marriages, but civil unions for gay and lesbian couples, as well.

Obama’s shift not only speaks to a broad swath of the electorate, which has exhibited increasing acceptance of same-sex marriage in opinion polls, but also gay and lesbian voters who compose a core part of Obama’s base, and have been major fundraisers for his re-election.

ABC News

President Barack Obama appears in an interview with ABC News on Wednesday, speaking in support of gay marriage. "It is important for me to go ahead and affirm that I think same sex couples should be able to get married," the president said.

Obama explained that he had hesitated in fully supporting same-sex marriage because he thought civil unions would be sufficient.

"I have to tell you that over the course of several years as I have talked to friends and family and neighbors when I think about members of my own staff who are in incredibly committed monogamous relationships, same-sex relationships, who are raising kids together, when I think about those soldiers or airmen or marines or sailors who are out there fighting on my behalf and yet feel constrained, even now that 'Don't Ask Don't Tell' is gone, because they are not able to commit themselves in a marriage, at a certain point I’ve just concluded that for me personally it is important for me to go ahead and affirm that I think same sex couples should be able to get married," he told ABC.

The president had found himself under increasing pressure this week to state his position unequivocally after Vice President Joe Biden voiced support for same-sex marriage.

"I am absolutely comfortable with the fact that men marrying men, women marrying women, and heterosexual men and women marrying another are entitled to the same exact rights, all the civil rights, all the civil liberties," Biden said on NBC’s "Meet the Press." "And quite frankly, I don't see much of a distinction beyond that."

While the White House emphasized that Biden’s position wasn’t representative of the entire administration, Education Secretary Arne Duncan’s pronouncement Monday on MSNBC’s “Morning Joe” in support of same-sex marriage added to pressure on the president.

“I have no update on the president's personal views,” press secretary Jay Carney said repeatedly at Monday’s White House press briefing in reference to the president’s self-styled “evolution” on gay marriage.

As a result, Obama has risked fallout among his political base. The Washington Post reported this week that gay and liberal donors had threatened to withhold financial support for the president or a super PAC due to his refusal to sign an executive order barring discrimination of gays and lesbians in federal contracting.

And Obama was expected, too, to encounter frustration at a major Hollywood fundraiser this week at the home of actor George Clooney.

The overwhelming approval, too, of the measure, which Obama had opposed, in North Carolina -- a key swing state -- heightened speculation that the president might address the issue.

RELATED: North Carolina approves ban on same-sex marriage

GOP presidential candidate Mitt Romney re-iterated his opposition to both same-sex marriage and civil unions on Tuesday.

"I have the same view on marriage that I had when I was governor and that I've expressed many times," he said following the president's announcement. "I believe marriage is a relationship between a man and a woman."

Earlier, he told KDVR-TV in Denver: "I do not favor marriage between people of the same gender, and I do not favor civil unions if they are identical to marriage other than by name ... My view is the domestic partnership benefits, hospital visitation rights, and the like are appropriate but that the others are not."

Obama has faced tremendous pressure throughout his administration to advance gay rights.

Among his earliest acts as president included signing an executive order extending benefits to federal employees in same-sex partnerships in 2009. Obama also ordered the government to stop defending the Defense of Marriage Act -- the 1996 laws allowing states to refuse to recognize same-sex marriages in other states -- in court.

The administration’s crowning achievement on gay rights came more methodically, though -- sometimes to the frustration of advocates for same-sex rights.

Obama signed the repeal of “Don’t Ask, Don’t Tell” -- the military’s ban on openly gay or lesbian service members -- into law in December 2010. But the repeal came after months of legislative wrangling, and the president’s refusal to sign a simple order to make the change. And even after Obama signed the law, the implementation took months.

FIRST READ: Is Obama's gay marriage stance all about suburban voters?

Same-sex marriage is hardly the hot-button issue it was compared to the last decade, though. Support for it now eclipses opposition; 49 percent of Americans said that favor allowing gays and lesbians to marry, according to the March NBC News/Wall Street Journal poll, while 40 percent oppose it. (In October 2009, 49 percent opposed same-sex marriages, while 41 percent supported them.)

Opinion has shifted especially among independent voters, who back marriage rights 46 percent to 37 percent. About three in 10 Republicans said they, too, support same-sex marriage.

However, of the 18 states making composing the “toss-up” or “lean” categories in NBC’s battleground map, 10 have banned same-sex marriage and civil unions outright, either by constitutional amendment or statute. Just two -- Iowa and New Hampshire -- have legalized gay marriage outright, while other states operate in more nebulous space when it comes to gay and lesbian couples.