The U.S. Supreme Court is hearing Monday arguments in a landmark case -- the -- debating the legality of President Barack Obama’s executive actions on immigration.
Roughly 4 million undocumented immigrants who are living in the United States.
The case focuses on Obama's 2014 program known as . The program defers deportation for undocumented immigrants who have been in the U.S. since at least 2010, have a child who is a U.S. citizen or is in the country legally, and do not have a criminal record.
Obama said he took executive action because Congress had failed to overhaul the immigration system.
Texas is leading 26 states as well as congressional Republicans in challenging Obama's executive actions. They argue Obama doesn't have the power to effectively change immigration law.
About 4 million people would be allowed to live and work in the U.S. temporarily without constant fear of deportation.
The lower court rulings, which have frozen the immigration actions, would likely stand through the remaining months of Obama's presidency.
A tie is possible after the death of Justice Antonin Scalia in February, which left eight members on the court. A tie would let the lower court rulings stand.
The high court also could decide that Texas and the other states don't have the right to sue in federal court, a procedural outcome that would largely sidestep the divisive immigration issue.
The court is expected to decide by late June.
Administration is represented by its top appellate lawyer, Solicitor General , who has argued many high-profile cases before the court, including the Affordable Care Act, the constitutionality of same-sex marriage and the Defense of Marriage Act.
The states are led by Texas’ solicitor general, , who has argued before the court regarding Texas' right to reject a proposal for license plates featuring a Confederate battle flag as well as in defense of Texas’ sharp restrictions on abortion clinics.
Candidates Donald Trump, Ted Cruz and John Kasich have said they would immediately reverse any actions allowed to take place.
Hillary Clinton and Bernie Sanders have said they would expand upon those efforts.