The U.S. Supreme Court will host oral arguments Wednesday in the case that may be the most consequential yet for the Trump administration’s agenda.

The case, Trump v. Hawaii, will decide the ultimate fate of President Donald Trump’s third travel ban, which prohibits travel from six Muslim-majority countries and North Korea. The nine justices will hear 30 minutes of argument from each side: the government, represented by Solicitor General Noel Francisco, and the assembled plaintiffs, represented by President Barack Obama’s one-time acting Solicitor General Neal Katyal.

The ban’s opponents, including the state of Hawaii and the George Soros-funded International Refugee Assistance Project, have tried to characterize it as a “Muslim Ban” and are challenging it on both First Amendment Establishment Clause and statutory grounds, using language of the Immigration and Nationality Act (INA). The U.S. Courts of Appeals for the Ninth and Fourth circuits have both already agreed with these opponents, striking down the bans repeatedly on statutory and constitutional grounds respectively. The Fourth Circuit was ruling on a similar case whose ultimate outcome will likely be determined by the outcome of this one.

Throughout the litigation in the lower courts, the bans’ opponents have sought to include President Trump’s words during and after the 2016 presidential campaign as evidence the ban is motivated by anti-Muslim animus and that this renders them illegal.

The travel ban case is the only one scheduled for arguments Wednesday. They should begin shortly after 10:00 a.m. Eastern time. The Supreme Court building is expected to be packed with press, lawyers, and members of the public, hoping to see the arguments, lining up some hours before.

The case has attracted an immense amount of popular attention and dozens of amicus briefs on both sides, but especially on the plaintiffs’. Libertarian groups like the Cato Institute have lined up with leftist organizations to urge the justices to invalidate the ban, which was a major campaign promise of Trump’s. None of the organizations who filed amicus briefs have been granted time for oral arguments.

A decision in the case is expected some time in June.

The case is Trump v. Hawaii, No. 17-965 at the Supreme Court of the United States.