As broadly as President Barack Obama may push the limits of his authority to shield from deportation millions of immigrants illegally in the United States, the fate of millions more will still be left unresolved.
Obama is preparing to flex his executive powers Thursday, using an 8 p.m. EST address to announce that he is sidestepping Congress and ordering his own federal action on immigration.
The reaction from congressional Republicans has been swift and fierce, heralding the start of what could be one of the most pitched partisan confrontations of Obama's presidency.
His measures could make as many as 5 million people eligible for work permits, with the broadest action likely aimed at extending deportation protections to parents of U.S. citizens and permanent residents, as long as those parents have been in the country for five years.
Other potential winners under Obama's actions would be young immigrants who entered the country illegally as children but do not now qualify under a 2012 directive from the president.
With more than 11 million immigrants living in the country illegally, Obama's actions would still leave millions unprotected even though their chances of getting deported if they have not committed a crime are low.
"What I'm going to be laying out is the things that I can do with my lawful authority as president to make the system better, even as I continue to work with Congress and encourage them to get a bipartisan, comprehensive bill that can solve the entire problem," Obama said in a video posted Wednesday on Facebook.
An executive action that makes parents of U.S. citizens and permanent residents eligible for work permits would affect about 3.3 million immigrants if it requires that they have lived in the U.S. for five years, according to the Migration Policy Institute. If the action includes spouses of U.S. citizens and permanent residents, the number of eligible immigrants rises to 3.8 million.
The president also is likely to expand his 2-year-old program that allowed immigrants under 31 who had arrived before June 2007 to apply for a reprieve from deportation and a work permit - a program that to date has shielded more than 600,000 young immigrants from deportation. One option under consideration would remove the upper age limit so applicants don't have to be under 31.
Obama's steps, however, would not include the parents of those young immigrants - a move many advocates had vigorously encouraged him to take. He also was not including special protections for farm workers sought by the United Farm Workers, though the provisions in his plan would allow up to 250,000 farm workers to be eligible for work permits, according to Giev Kashkooli, the UFW's national political legislative director.
As far-reaching as Obama's steps would be, they fall far short of what a comprehensive immigration overhaul passed by the Senate last year would have accomplished. The House never voted on that legislation. It would have set tougher border security standards, increased caps for visas for foreign high-skilled workers and allowed the 11 million immigrants illegally in the country to obtain work permits and begin a 10-year path toward a green card and, ultimately, citizenship.
None of those affected by Obama's actions would have a path to citizenship, and the actions could be reversed by a new president after Obama leaves office. Moreover, officials said the eligible immigrants would not be entitled to federal benefits - including health care tax credits - under Obama's plan.
Some immigrant advocates worried that even though Obama's actions would make millions eligible for work permits, not all would participate out of fear that Republicans or a new president would reverse Obama's actions.
"If the reaction to this is that the Republicans are going to do everything they can to tear this apart, to make it unworkable, the big interesting question will be will our folks sign up knowing that there is this cloud hanging over it," said Janet Murguia, president and CEO of the National Council of La Raza.
Still, Democrats battered by election losses two weeks ago welcomed Obama's steps.
"The last two weeks haven't been great weeks for us," said Rep. Joe Crowley of New York, one of 18 congressional Democrats who had dinner Wednesday night with Obama. "The president is about to change that."
While Republicans vehemently oppose the president's likely actions, they are deeply divided over how to respond. Some conservative members have threatened to pursue a government shutdown, and one - two-term Republican Rep. Mo Brooks of Alabama - raised the specter of impeachment Wednesday.
Even Republicans who supported the Senate bill that would have overhauled immigration laws said Obama's go-it-alone approach would backfire. Still, they cautioned their party colleagues not to overreach in their response.
Sen. Lindsey Graham, R-S.C., who worked on the Senate legislation, said the executive actions would leave the status of millions of immigrants unresolved and would not address what he called a broken immigration system.
"Our response has to be measured - can't capitulate, can't overreact," he said. "Impeachment or shutting down the entire government would be an unwise move."
Former President Bill Clinton noted Wednesday that previous U.S. presidents have issued executive orders on immigration. He said he thought Obama was on "pretty firm legal footing."
Among the tools available to Republicans, who will have majorities in the House and Senate at the start of the year, are spending bills. A current spending measure to keep the government running expires next month and one option was to approve another short-term spending bill until February, when Republicans are in full control of Congress.
"We're looking at what our levers are, and that's clearly the funding power," said Sen. John Cornyn of Texas, a member of the Senate Republican leadership. He added, however, "None of us want any unnecessary drama associated with the funding process."