David Jackson and Alan Gomez

USA TODAY

WASHINGTON — President Obama took a historic, legacy-defining step Thursday night when he announced a plan to protect 5 million undocumented immigrants from deportation, infuriating Republicans but satisfying immigrants who have fought for years for such relief.

The president's plan will allow undocumented immigrants who are parents of U.S. citizens and legal permanent residents, known as green card holders, to legally live and work in the country for a period of three years. He expanded the pool of undocumented immigrants brought to the country as children who are eligible for protected status.

The plan makes it easier for foreign workers trained in high-tech fields to enter, and stay in, the country. And it refocuses the nation's entire immigration enforcement apparatus on a much smaller pool of immigrants — those with criminal records, ties to terrorist organizations or gangs and people who crossed the border in the past year.

"Mass amnesty would be unfair. Mass deportation would be both impossible and contrary to our character. What I'm describing is accountability — a common-sense, middle-ground approach," Obama said from the East Room of the White House. "If you meet the criteria, you can come out of the shadows and get right with the law. If you're a criminal, you'll be deported. If you plan to enter the U.S. illegally, your chances of getting caught and sent back just went up."

Republicans in Congress promised to do everything in their power to block the president's actions. Some have called for impeachment. Some want to sue the president in federal court. As Washington is in the middle of debating next year's budget, some want to use Congress' power of the purse to defund his move.

"By ignoring the will of the American people, President Obama has cemented his legacy of lawlessness and squandered what little credibility he had left," said House Speaker John Boehner, R-Ohio. "Republicans are left with the serious responsibility of upholding our oath of office. We will not shrink from this duty, because our allegiance lies with the American people. We will listen to them, work with our members and protect the Constitution."

Obama said he was forced to act because of Congress' inability to pass a bill to overhaul the nation's broken immigration system.

The Senate passed such a bill last year that would have allowed 8 million undocumented immigrants to become U.S. citizens and dedicated $38 billion to increase border security. That bill was rejected by Boehner, and the chamber failed to consider any plan of its own.

There is serious disagreement over the legality of Obama's move.

The White House pointed to the actions of previous presidents, including Republicans Ronald Reagan and George H.W. Bush, who issued executive orders granting legal status to migrants. The White House counsel's office has vetted the plan, and it is confident the orders can withstand legal scrutiny.

"The actions I'm taking are not only lawful, they're the kinds of actions taken by every single Republican president and every Democratic president for the past half-century," Obama said.

The Republican position: Reagan and Bush did executive orders as adjustments to a congressional immigration bill passed in 1986, while Obama is going around Congress. Some described the new executive orders as a political power grab designed to appeal to Hispanic voters.

GOP members pointed out that, in recent years, Obama himself has questioned whether he has the legal authority to defer deportations.

"President Obama is going rogue, doubling-down and driving full-speed towards a constitutional crisis," said Rep. Bob Goodlatte, R-Va., chairman of the House Judiciary Committee that handles immigration legislation. "By assuming legislative power and ignoring the limitations placed on his authority, President Obama threatens to unravel our government's system of checks and balances and imperils individual liberty."

The president's plan will focus first on granting protections to nearly half of the nation's 11 million undocumented immigrants.

Obama created a program in 2012, known as Deferred Action for Childhood Arrivals, or DACA, that allowed undocumented immigrants brought to the country as children to register with the federal government, pass a criminal background test and pay a fee in exchange for temporary legal status and a work permit.

The new plan expands that program to include undocumented immigrants who are parents of U.S. citizens and green-card holders. None of the beneficiaries of Obama's plan would be eligible for U.S. citizenship or green cards, but they will receive work permits, Social Security numbers and have the guarantee that, unless they commit a serious criminal offense, they will not be deported.

The plan does not include any relief for parents of DACA recipients, nor does it help childless undocumented immigrants who have been in the country for long periods of time, two populations that immigration advocacy had been hoping to protect.

The administration will change regulations that dictate how foreign workers trained in high-tech fields can enter, and stay in, the country.

Before, foreign workers were sponsored by American employers, but it was a difficult process to find a new job and start over with a new employer. Obama's plan will allow for more "portability," making it easier for them to find different jobs.

The new plan will change the way foreign entrepreneurs can enter the country. They must prove they will invest a certain amount of money – for some visas, that can range up to $1 million. Under the new plan, entrepreneurs can use American investors as their basis to get into the country.

The plan does not include expansions of programs that deal with lower-skilled workers that would benefit the agriculture, construction and retail industries, which have requested new rules for years.

The bill would change the way the Departments of Homeland Security and Justice deal with immigration enforcement.

DHS Secretary Jeh Johnson will lay out a set of immigration enforcement priorities, ensuring Border Patrol agents, Immigrations and Customs Enforcement officers and U.S. attorneys will focus their deportation efforts almost exclusively on undocumented immigrants who pose a threat to national security, are members of gangs or have serious criminal records.

"Felons, not families. Criminals, not children. Gang members, not a mom who's working hard to provide for her kids," Obama said. "We'll prioritize, just like law enforcement does every day."

Homeland Security will alter and rename a controversial program called Secure Communities that allows police agencies to check whether people they're arresting have outstanding immigration violations on their record. The new program will be called Priority Enforcement Program, or PEP.

Before, anybody arrested who had immigration violations had an automatic "detainer" placed on them, allowing an ICE officer to come pick them up. Now, immigration violations will only trigger a "notification," and ICE officers will pick them up only if they fit into one of the new, more limited enforcement priorities.

Obama said he wants to work with Congress on a legislative bill that would supersede the executive orders.

"I want to work with both parties to pass a more permanent legislative solution. And the day I sign that bill into law, the actions I take will no longer be necessary," Obama said. "Meanwhile, don't let a disagreement over a single issue be a deal breaker on every issue. That's not how our democracy works, and Congress certainly shouldn't shut down our government again just because we disagree on this."

Listen to audio of President Obama's speech here: