Mr. Obama will frame the new effort — likely to rouse passions on all sides of the highly divisive issue — as “policy reform that controls immigration and makes it an orderly system,” said the official, Cecilia Muñoz, deputy assistant to the president and director of intergovernmental affairs in the White House.
Mr. Obama plans to speak publicly about the issue in May, administration officials said, and over the summer he will convene working groups, including lawmakers from both parties and a range of immigration groups, to begin discussing possible legislation for as early as this fall.
Some White House officials said that immigration would not take precedence over the health care and energy proposals that Mr. Obama has identified as priorities. But the timetable is consistent with pledges Mr. Obama made to Hispanic groups in last year’s campaign.
He said then that comprehensive immigration legislation, including a plan to make legal status possible for an estimated 12 million illegal immigrants, would be a priority in his first year in office. Latino voters turned out strongly for Mr. Obama in the election.
“He intends to start the debate this year,” Ms. Muñoz said.
But with the economy seriously ailing, advocates on different sides of the debate said that immigration could become a polarizing issue for Mr. Obama in a year when he has many other major battles to fight.
Opponents, mainly Republicans, say they will seek to mobilize popular outrage against any effort to legalize unauthorized immigrant workers while so many Americans are out of jobs.
Democratic legislative aides said that opening a full-fledged debate this year on immigration, particularly with health care as a looming priority, could weigh down the president’s domestic agenda.
Debate is still under way among administration officials about the precise timing and strategy. For example, it is unclear who will take up the Obama initiative in Congress.
No serious legislative talks on the issue are expected until after some of Mr. Obama’s other priorities have been debated, Congressional aides said.
Just last month, Mr. Obama openly recognized that immigration is a potential minefield.
"I know this is an emotional issue; I know it’s a controversial issue,” he told an audience at a town meeting on March 18 in Costa Mesa, Calif. “I know that the people get real riled up politically about this."
But, he said, immigrants who are long-time residents but lack legal status “have to have some mechanism over time to get out of the shadows.”
The White House is calculating that public support for fixing the immigration system, which is widely acknowledged to be broken, will outweigh opposition from voters who argue that immigrants take jobs from Americans. A groundswell among voters opposed to legal status for illegal immigrants led to the defeat in 2007 of a bipartisan immigration bill that was strongly supported by President George W. Bush.
Administration officials said that Mr. Obama’s plan would not add new workers to the American work force, but that it would recognize millions of illegal immigrants who have already been working here. Despite the deep recession, there is no evidence of any wholesale exodus of illegal immigrant workers, independent studies of census data show.
Opponents of legalization legislation were incredulous at the idea that Mr. Obama would take on immigration when economic pain for Americans is so widespread.
“It just doesn’t seem rational that any political leader would say, let’s give millions of foreign workers permanent access to U.S. jobs when we have millions of Americans looking for jobs,” said Roy Beck, executive director of NumbersUSA, a group that favors reduced immigration. Mr. Beck predicted that Mr. Obama would face “an explosion” if he proceeded this year.
“It’s going to be, ‘You’re letting them keep that job, when I could have that job,’ ” he said.
In broad outlines, officials said, the Obama administration favors legislation that would bring illegal immigrants into the legal system by recognizing that they violated the law, and imposing fines and other penalties to fit the offense. The legislation would seek to prevent future illegal immigration by strengthening border enforcement and cracking down on employers who hire illegal immigrants, while creating a national system for verifying the legal immigration status of new workers.
But administration officials emphasized that many details remained to be debated.
Opponents of a legalization effort said that if the Obama administration maintained the enforcement pressure initiated by Mr. Bush, the recession would force many illegal immigrants to return home. Dan Stein, the president of the Federation for American Immigration Reform, said it would be “politically disastrous” for Mr. Obama to begin an immigration initiative at this time.
Anticipating opposition, Mr. Obama has sought to shift some of the political burden to advocates for immigrants, by encouraging them to build support among voters for when his proposal goes to Congress.
That is why Representative Luis V. Gutierrez, a Democrat from Mr. Obama’s hometown, Chicago, has been on the road most weekends since last December, traveling far outside his district to meetings in Hispanic churches, hoping to generate something like a civil rights movement in favor of broad immigration legislation.
Mr. Gutierrez was in Philadelphia on Saturday at the Iglesia Internacional, a big Hispanic evangelical church in a former warehouse, the 17th meeting in a tour that has included cities as far flung as Providence, R.I.; Atlanta; Miami; and San Francisco. Greeted with cheers and amens by a full house of about 350 people, Mr. Gutierrez, shifting fluidly between Spanish and English, called for immigration policies to preserve family unity, the strategic theme of his campaign.
At each meeting, speakers from the community, mainly citizens, tell stories of loved ones who were deported or of delays and setbacks in the immigration system. Illegal immigrants have not been invited to speak.
Mr. Gutierrez’s meetings have all been held in churches, both evangelical and Roman Catholic, with clergy members from various denominations, including in several places Muslim imams. At one meeting in Chicago, Cardinal Francis George, president of the United States Conference of Catholic Bishops, officiated.
One speaker on Saturday, Jill Flores, said that her husband, Felix, an immigrant from Mexico who crossed the border illegally, had applied for legal status five years ago but had not been able to gain it even though she is an American citizen, as are their two children. Now, Ms. Flores said, she fears that her husband will have to leave for Mexico and will not be permitted to return for many years.
In an interview, Mr. Gutierrez rejected the idea that the timing is bad for an immigration debate. “There is never a wrong time for us,” he said. “Families are being divided and destroyed, and they need help now.”