Democrats back Obama as he readies immigration plan

WASHINGTON (Reuters) - President Barack Obama planned on Thursday to ease the threat of deportation for about 4.7 million illegal immigrants, as leading Democrats lined up behind the U.S. leader in the face of Republican attacks.

In a speech to be broadcast at 8 p.m. ET (0100 GMT), Obama will announce he will use his executive authority to allow these undocumented residents to legally apply for jobs and join American society, but without any guarantee of permanent residency or citizenship.

Top Democrats, including Senate Majority Leader Harry Reid, rallied behind Obama. "We've got his back," Reid said of the coming battle with Republicans enraged by the move.

The president will need the support of Democratic lawmakers to fend off Republican attempts, either next month or next year, to pass legislation undercutting the executive action.

Obama dispatched his chief of staff, Denis McDonough, to Capitol Hill for lunch with Senate Democrats who grilled him on the politics and policy behind his unilateral move.

Senator Chris Murphy of Connecticut told reporters there was discussion during that lunch about the need to avoid getting into a "defensive position" amid the barrage of Republican salvos.

"We've got to go out and sell why this is constitutional and a policy imperative," Murphy said.

Obama's plan would let approximately 4.4 million parents of U.S. citizens and legal permanent residents remain in the United States temporarily, without the threat of deportation, a source briefed by the administration told Reuters.

Democratic Senator Richard Durbin of Illinois said he was informed that the program will apply to those who have been in the United States for at least five years.

According to the source who asked not to be identified, an additional 270,000 people would probably qualify for an expansion of a 2012 move by Obama to stop deporting people brought illegally to the United States as children by their parents.

REPUBLICAN CHALLENGE

The leading Republican in the Senate, Mitch McConnell, in a speech on the Senate floor, warned that Congress would move to thwart Obama's unilateral actions, which Republicans argue go beyond the president's authority.

But McConnell did not provide details.

Even with a more muscular Republican Party next year that will control both the House of Representatives and the Senate, it was unclear how they would try to undo Obama's initiative, or whether they would have the clout.

Republicans have discussed using some must-pass spending bills to hamstring Obama, but they have been running into political and technical roadblocks with many of their ideas.

The result could be two solid years of sniping at Obama's initiative without actually changing it, similar to the past four years of Republican attempts to repeal the "Obamacare" healthcare program that became law in 2010.

Republican Representative Pat Tiberi of Ohio accused Obama of "an intentional effort ... to throw a grenade in the middle of our Republican conference" by taking unilateral action. But Tiberi acknowledged that Republicans had yet to come up with a unified legislative response.

Obama also must look out for opposition from fellow Democrats.

Senator Angus King of Maine, an independent who aligns himself with Democrats, said McDonough was peppered with questions about the president's new immigration policy.

"I'd say people stated their views strongly, but I wouldn't call it contentious. Nobody threw anything," King told reporters.

Some Democratic senators representing conservative states have expressed concerns over Obama's timing.

LEGAL DIFFERENCES

Legal experts were divided on whether Obama was overstepping his authority.

University of California Law Professor John Yoo, a former Bush administration official, said, "That is an exercise of executive power that even the most stalwart defenders of an energetic executive, not to mention the (U.S. Constitution's) framers, cannot support."

Kari Hong, a professor at Boston College Law School, countered, "Legally, Obama is on exceedingly strong footing in terms of the legal and constitutional authority and past practices."

For months, Obama has warned he would take the steps after House Republicans blocked a comprehensive, bipartisan immigration bill passed by the Senate in 2013. On Thursday, Democrats were eager to underscore that 511 days had gone by without House action.

Meanwhile, Republican governors meeting in Boca Raton, Florida, said they would discuss the possibility of suing Obama to stop his actions. Potential presidential candidates Scott Walker of Wisconsin and Rick Perry of Texas both have expressed support of legal action.

According to sources, Obama's plan includes measures designed to benefit high-tech businesses, which have long complained about cumbersome immigration laws. But the measures fell short of what the tech industry had hoped for.

(Writing by Richard Cowan, additional reporting by Amanda Becker in Washington and Mica Rosenberg in New York; Editing by Tom Brown and Howard Goller)