Shortly after President Donald Trump took office, he signed an executive order that temporarily barred immigration from seven Muslim-majority countries. The original order, which became widely known as the “travel ban,” prompted confusion and mass protest at airports across the country. Since then, the order has gone through a wringer of litigation, prompting the Trump administration to roll out revised versions of the original plan.

After more than a year of back and forth in the courts, the Supreme Court decided to take up challenges on the third and latest version, which took effect in December. The third version would impose a permanent ban on most immigrants from Iran, Libya, North Korea, Somalia, Syria, Venezuela and Yemen.

Here’s a rundown of what to expect as the Supreme Court hears arguments in Trump v. Hawaii.

Who is involved: The petitioner is the federal government, whose arguments will be presented by Solicitor General Noel Francisco. The respondents are the state of Hawaii, representing multiple impacted parties; the attorney Neal Katyal, who served as acting solicitor general under President Barack Obama, will present their arguments.

READ MORE: The constitutional showdown over President Donald Trump’s travel ban

History of litigation: The travel ban has gone through three versions. The one being heard Wednesday by the Supreme Court is the third and latest iteration. The first two travel bans were challenged in federal district courts and found to be unlawful. The United States Court of Appeals for the 9th and 4th Circuits upheld the lower court rulings, invoking injunctions that prevented the Trump administration from carrying the orders out. The White House appealed both decisions. This is the second time the Supreme Court has agreed to weighed in on the travel ban. The court initially agreed to hear arguments on the second version, which would have been on the docket in October. But the government rolled out the third version in September, making the second version moot.

The federal government’s argument: There will be one hour of arguments. The government, as the appellant, will present its case first. The government will argue that the president has authority over matters of immigration and foreign policy, and that the court does not have the authority to review this policy. Francisco is also expected to argue that the policy is within the president’s power under the Immigration and Nationality Act. He will likely also bring up the justifications outlined in the Trump administration’s executive order — that the ban was instituted in the interest of national security — and argue that the justification was legitimate.

The respondents’ argument: Following the government, Katyal will present Hawaii’s arguments. He is expected to argue that the travel ban violates the Establishment Clause of the First Amendment, which prevents the government from preferring one religion over another. Katyal will argue that the executive order is also a de facto ban on Muslim immigrants, something the Trump administration has denied. But Katyal is expected to point out that though the executive order doesn’t explicitly target Muslims, the ban on immigration from the Muslim-majority countries of Iran, Libya, Somalia, Syria and Yemen was motivated by anti-Muslim sentiment. After Katyal presents Hawaii’s arguments, the government will be given a rebuttal and that will bring the arguments to a close.

When will the court make a decision? There is no specific date, but a ruling is expected before the court’s term ends in June.