LAS VEGAS - US President Barack Obama staunchly defended his unilateral move to shield millions of undocumented immigrants from deportation Friday, pledging to implement his controversial plan despite furious criticism from congressional opponents.
The controversial overhaul, praised by many immigration rights activists, provides three-year relief for millions of undocumented people who have lived in the country for more than five years and have children that are US citizens or legal residents.
According to the president, it also channels more resources to the US border with Mexico and shifts deportation priorities toward expelling felons.
"I have come back to Del Sol to tell you, I'm not giving up. I will never give up," Obama insisted at the Las Vegas, Nevada high school where he launched his immigration reform efforts two years ago.
"We're going to keep on working with members of Congress to make permanent reform a reality," he added.
"But until that day comes, there are actions that I have the legal authority to take that will help make our immigration system more fair and more just, and this morning I began to take some of those actions." He wasted little time, signing two elements of the orders.
"Don't let all the rhetoric fool you," Obama said, referring to repeated Republican claims that the administration has done little to beef up border security or stem illegal crossings.
Obama said the overall number of people trying to cross illegally was now at its lowest level since the 1970s.
Crucially, the reforms do not offer a pathway to citizenship, something Obama was quick to point out to the largely-Hispanic American crowd after they broke into chants of "Si se puede" - the Spanish version of his original 2008 campaign slogan "Yes we can." Republicans have nevertheless heaped scorn on the plan, calling it "executive amnesty," "illegal" and "unconstitutional," bringing tensions between Washington's warring camps to a boil.
Already emboldened by their sweeping midterm election victory, Republicans vowed to thwart Obama's plans.
"With this action, the president has chosen to deliberately sabotage any chance of enacting bipartisan reforms he claims to seek," House Speaker John Boehner declared.
"I will say to you: the House will in fact act."
'Illegal power grab'
In a primetime address Thursday, Obama noted that nearly a dozen commanders-in-chief before him have acted unilaterally over the past half century on some facet of immigration reform.
Republicans are not buying it.
"The constitution does not grant the president the power to act as a one-man legislature by appealing to 'tradition,'" Republican National Committee Chairman Reince Priebus fumed on Twitter.
Under the new rules, people living and working illegally in the country and who meet the criteria can apply for deferred deportation from next spring.
"The president is going to undertake a very aggressive sales job on the actions he announced last night," White House senior advisor Daniel Pfeiffer said at a reporters' breakfast, adding that Obama saw immigration as an "incredibly important" priority.
The political firestorm unleashed by Obama does not bode well for relations between Congress and the White House in the coming months.
Boehner provided no specifics about Republican countermeasures, but others have laid out options, including seeking to defund the offices responsible for carrying out Obama's efforts.
Some want to insert language in must-pass spending legislation that would block the executive action, setting up a showdown that could lead to a government shutdown.
Lawmakers should push back against Obama's "illegal power-grab," said Republican Senator John McCain, who helped craft immigration legislation that passed the Senate but died in the Republican House.
He has warned against provoking another shutdown like one in 2013 that was blamed on Republicans.
"Congress must be creative in using all the tools in our toolbox - including mounting a legal challenge - to oppose the president's action," McCain said.
Conservative Senator Ted Cruz called for blocking Obama's choices for ambassadorial and administration posts, as well as judgeships.
And some, like immigration reform foe congressman Steve King, have even floated the idea of impeachment.
Boehner himself sent a stern political message Friday about the president's executive overreach, announcing that House Republicans have filed suit in federal court challenging changes the administration made to the Affordable Care Act.
Obama's action was welcomed warmly in Latin America.
"This seems to me to be an act of justice that recognizes the great contributions made by millions of Mexicans to the development of our North American neighbor," said Mexican President Enrique Pena Nieto.
Ecuador said his country had "a certain level of hope" following Obama's offer.
"I'm very happy that President Obama has said that there will not be mass deportation. This seems very good," Foreign Minister Ricardo Patino said.