(AP) -- Conservative Supreme Court justices expressed sharp skepticism about President Barack Obama's immigration efforts Monday, leaving his actions to help millions of people who are in the country illegally in the hands of a seemingly divided court.

As hundreds of pro-immigration demonstrators and a smaller number of opponents filled the sidewalk outside the court, the justices appeared to split along ideological and partisan lines over a case that pits Republican governors and members of Congress against the Democratic administration.

President Barack Obama's administration is asking the justices to allow it to put in place two programs that could shield roughly 4 million people from deportation and make them eligible to work in the United States.

Texas is leading 26 states led by Republicans in challenging the programs that Obama announced in 2014 and that have been put on hold by lower courts. Those states say the administration usurped power that belongs to Congress, and Justice Anthony Kennedy indicated some support for that view.

"It's as if ... the president is setting the policy and the Congress is executing it. That's just upside down," Kennedy said.

Chief Justice John Roberts also aggressively questioned Solicitor General Donald Verrilli Jr., suggesting there are few limits to the president's power under the administration's view of immigration law.

"Under your argument, could the president grant deferred removal to every ... unlawfully present alien in the United States right now?" Roberts asked.

"Definitely not," Verrilli said. But it was not clear Roberts was satisfied with the answer and subsequent explanation.

The programs would apply to parents of children who are citizens or are living in the country legally. Eligibility also would be expanded for the president's 2012 effort that applies to people who were brought here illegally as children. More than 700,000 people have taken advantage of that earlier program, Deferred Action for Childhood Arrivals. The new program for parents, known as Deferred Action for Parents of Americans, and the expanded program for children could reach as many as 4 million people, according to the nonpartisan Migration Policy Institute.

If the court is split ideologically, the case could end in a 4-4 tie following Justice Antonin Scalia's death in February. That would leave the programs in limbo, almost certainly through the end of Obama's presidency.

Both sides acknowledge that the outcome of the presidential election ultimately could determine the programs' fates, even if the Supreme Court rules for the administration. Republican candidates have pledged to roll back Obama's actions, and Republican candidate Donald Trump has proposed deporting the roughly 11 million people who are living in the U.S. illegally.

Several justices remarked how Congress provides enough money to deport only about 400,000 people annually.

The bulk of immigrants who live in the U.S. illegally "are here whether we want them or not," Justice Sonia Sotomayor said.

The high court is expected to decide by late June whether the efforts can move forward in the waning months of Obama's presidency.

Roberts and his colleagues might have an incentive to avoid a tie vote that would not set a nationwide precedent and also point to the short-handed court's difficulty in getting its work done. If that's the case, the fate of the programs could hang on a two-word phrase the administration used to describe the status of immigrants under the programs-- lawful presence. Texas and congressional Republicans who back the state say the phrase is important because it gives the immigrants more rights than federal law allows.

Verrilli told the justices that they could get rid of the phrase and essentially leave the programs unchanged. "If the court thinks it's a problem and wants to put a red pencil through it, it's totally fine," he said.

Roberts sounded interested in that idea, asking lawyer Erin Murphy if the court could, in fact, just "cross out the phrase."

Murphy, representing House Republicans, said it wasn't that simple.

In fact, it was not clear from the arguments whether such an outcome would affect immigrants' ability to work or receive other benefits, including Social Security.

One way for the court to avoid dipping into the complex details of immigration law would be to adopt the administration's argument that Texas has no right to challenge the programs in federal court.

But Roberts did not seem interested in that idea, noting that a ruling on the technical issue of standing would put Texas in a "Catch-22."

Republican governors and members of Congress have argued that Obama doesn't have the power to effectively change immigration law. When he announced the measures 17 months ago, Obama said he was acting under his own authority because Congress had failed to overhaul the immigration system. The Senate had passed legislation on a bipartisan vote, but House Republicans refused to put the matter to a vote.

The administration and immigration advocates say Obama's orders are neither unprecedented nor even unusual. Rather, they say, the programs build on past efforts by Democratic and Republican administrations to use discretion in deciding whom to deport.

The protection from deportation is "discretionary, temporary and revocable relief from the daily fear that they will be separated from their families," Thomas Saenz, arguing on behalf of three mothers of U.S. citizen children, told the court.