For years, Roberto Guzman was afraid to drive to class at Sacramento City College for fear he would be pulled over and deported to Mexico.

Now Guzman – whose parents brought him to California from Zacatecas state when he was 2 – is among thousands of undocumented immigrants breathing easier.

The Obama administration announced last week that it would deport only those "who pose a threat to public safety and national security."

That means Guzman, 19, and millions of other undocumented immigrants in the United States will no longer be targeted for deportation. About 300,000 undocumented immigrants facing possible deportation will be reconsidered on a case-by-case basis.

How long this review will take – and who exactly will be allowed to stay – is unknown. Those subject to "prosecutorial discretion" – meaning they are no longer a law enforcement priority – include a significant number of the nation's 12 million undocumented immigrants, including: Veterans and those serving in the military; minors and the elderly; pregnant or nursing women; victims of domestic violence, trafficking or other serious crimes; those suffering from serious mental or physical disabilities and illnesses; and those in the United States since childhood.

"I was really ecstatic," said Guzman, who leads Sac City's Dream Team Club – about 20 undocumented students fighting for legalization. "A lot of people I know didn't like driving because they put themselves at risk of being caught. Now I can drive freely to the store and relieve some of this fear."

Those seeking to crack down on illegal immigration say President Barack Obama's decision will allow a wide range of people to remain in this country illegally. They accuse Obama of running "an imperial presidency" by trumping laws passed by Congress that make it illegal to be here without papers.

"Basically anybody who has not committed a violent crime is now safe from removal," said Ira Mehlman, spokesman for the Federation for American Immigration Reform, which has 250,000 members nationwide.

Mehlman conceded that students such as Guzman "are in a difficult situation," but added, "It was their parents that put them in that situation by deciding to break the law."

By not subjecting these students to deportation unless they've committed a serious crime, he said, "the signal is to bring your kids to the U.S., get them through a few years of school, and they're going to get green cards."

The DREAM (Development, Relief and Education for Alien Minors) Act, which would legalize those students, has been proposed since 2000 and hasn't passed Congress, Mehlman noted. A slight majority of Americans, 54 percent, back the DREAM Act, acording to a December Gallup poll.

Obama maintains "it makes no sense to expend enforcement resources on low-priority cases, such as individuals who were brought to this country as small children and who know no other home," said Director of Homeland Security Janet Napolitano.

"Doing so otherwise hinders our public safety mission – clogging immigration court dockets and diverting DHS enforcement resources away from individuals who pose a threat to public safety," Napolitano said.

The administration's new priorities are working, she said. Last year, Immigration and Customs Enforcement removed 79,000 more illegal immigrants convicted of crimes than it did in 2009. ICE will still deport repeat offenders who keep re-entering the United States.

Guzman – a mentor in Sacramento City College's Puente program, which helps students transfer to four-year colleges – said the administration's ruling has given him hope he can become an immigration lawyer.

California State University, Sacramento, graduate Maria Luna, who was just 3 days old when her parents brought her from Mexicali, said there are an estimated 2 million undocumented youths like her nationwide.

"It gives us so much hope," Luna, 23, said of the Obama announcement. "A lot of students were afraid to be out in public."

Mandeep Chahal, a pre-med student at the University of California, Davis, called the Obama administration's decision a significant first step. Chahal came within a few hours of being deported earlier this year before the federal government granted her and her mother a stay.

"It's amazing how much everything has changed in just a couple of months," said Chahal, 20, who was 6 when her mother brought her to California from India's Punjab region.

Chahal hopes to become a pediatrician serving low-income and underrepresented communities, she said, "but I'm not going to be able to practice medicine and help anyone if I don't have any legal status or work authorization."

Significant questions remain about how the federal government will implement its new policy, said UC Davis Law School Dean Kevin Johnson.

"What kind of criminal violations are they going to focus on? Are they going to make distinctions between driving without a license and murder?" he asked.

Before the change in priorities, undocumented immigrants arrested for driving without a license could be deported because of their status, Johnson said.

The same is true of people caught in domestic violence, such as the young mother from Lodi who was deported in a matter of days for fighting with her common-law husband, who was also deported, Johnson said.

"It's not clear what the government's going to do with those cases," he said. "But it is clear you can't remove 11 million people from the country."

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