The most sweeping, controversial step under consideration involves halting deportation for millions, a major expansion of a 2012 Obama program that deferred prosecutions for those brought here illegally as children.
Roughly half a million people have benefited from that program, known as Deferred Action for Childhood Arrivals, or DACA.
In a sign of how heated the demands on Obama to act have become, 145 protesters were arrested midday Thursday in front of the White House in an act of civil disobedience. Demanding a halt to deportations, protesters draped themselves in American flags and held signs saying "I am a witness for justice" as onlookers cheered them on. The U.S. Park Police said the protesters were charged with blocking the sidewalk.
Republicans are already hinting they'll consider legal action to thwart what they've denounced as a violation of the separation of powers. House Speaker John Boehner, R-Ohio, in a conference call this month with GOP House members, accused Obama of "threatening to rewrite our immigration laws unilaterally."
"If the president fails to faithfully execute the laws of our country, we will hold him accountable," Boehner said, according to an individual who participated in the call.
Sen. Bill Nelson, D-Fla., predicted Thursday that Congress would not tackle an immigration overhaul before the fall elections.
"There are too many members of the House that are scared of the tea party, and they are afraid to death that they won't get the extremist support in the election," Nelson told reporters in Orlando, Florida. "There is nothing being done on immigration until after the election, and probably not until we get a better sense of where we're going into next year."
The House has passed legislation to block Obama from expanding DACA and, through its power of the purse, could attempt to cut off the funds that would be needed to implement the expansion. House Republicans could also consider widening or amending their existing lawsuit against Obama over his health care law, a case both parties have suggested could be a prelude to impeachment proceedings.
Associated Press writers Josh Lederman in Washington and Michael Schneider in Orlando, Florida, contributed to this report.
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