WASHINGTON (Reuters) - The Obama administration said on Tuesday it plans to ask the U.S. Supreme Court to reverse an appeals court decision that blocked President Barack Obama’s executive actions aimed at shielding millions of illegal immigrants from deportation.

A woman holds a replica green card sign during a protest march to demand immigration reform in Hollywood, Los Angeles, California, October 5, 2013. REUTERS/Lucy Nicholson

The Justice Department said it will appeal a 2-1 decision by the New Orleans-based 5th U.S. Circuit Court of Appeals on Monday affirming a lower court’s decision halting Obama’s immigration actions.

The legal challenge to Obama’s actions was made by 26 Republican-governed states that contend the president exceeded his presidential powers by bypassing Congress and acting unlilateraly.

Obama’s executive orders, announced last November but put on hold by the courts, would let up to 4.7 million undocumented immigrants live in the United States without the threat of deportation. It was aimed mainly at helping people whose children are U.S. citizens.

The challenge succeeded in putting Obama’s actions on hold just before they were due to go into effect in February.

Senate Judiciary Committee Chairman Chuck Grassley, an Iowa Republican, said the 5th Circuit ruling was a “win for the checks and balances established by the Constitution.”

The Obama administration has said the president did not overstep his authority by asking the Department of Homeland Security to use discretion before deporting nonviolent illegal immigrants with U.S. family ties.

“We continue to believe strongly in the legal power of the arguments we’ve been making for nearly a year now,” said White House spokesman Josh Earnest.

The immigration issue has driven a wedge between Hispanics, a voting bloc with increasing clout, and Republicans, many of whom take a hard line on illegal immigration, to the benefit of Obama’s fellow Democrats. Most of the estimated 11 million illegal immigrants are Hispanic.

In the race for the 2016 Republican presidential nomination, candidate Donald Trump and others have talked tough about illegal immigration. Trump has vowed to build a wall on the U.S.-Mexico border and deport all illegal immigrants.

Democratic presidential candidate Hillary Clinton said on Tuesday she hoped Obama’s executive actions will prevail.

Questions remain over whether the Supreme Court will hear the case, how the justices will rule and how the program might then be implemented, depending on the decision, in a short time frame.

For the case to be heard during the court’s current session, which runs through June, the administration and the state challengers would have to file legal papers quickly.

John Elwood, a partner at Vinson & Elkins law firm who has argued nine cases before the justices, said, “The government would have to file its brief essentially this month.”

The court typically stops taking cases for the current term in mid-January. Cases accepted after that go to the next term, beginning in October.

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If the court hears the case this term, a ruling would be expected by the end of June.

If the administration were to prevail, it would have until the January 2017 end of Obama’s term to process millions of immigrants who may be eligible for the program.

“The question will be whether or not the administration can staff up in time,” said Ali Noorani, executive director of the National Immigration Forum in Washington. “There’s going to be tremendous pressure to deliver.”