The US Court of Appeals for the Fourth Circuit heard oral arguments Tuesday in Intl Refugee Assistance v. Donald Trump, which is centered largely on the travel bans.

The plaintiffs in this case argue that, despite the Supreme Court ruling in Trump v. Hawaii, their case is not barred. They argue that the court simply addressed the preliminary injunction, and not the merits of the overall travel ban.

The case challenges the proclamation Protecting the Nation from Foreign Terrorist Entry into the United States from Executive Order 13780.

A major issue raised in this case is whether the District Court applied the proper legal standard in using rational basis review in evaluating the case. The plaintiffs are arguing that the proclamation is unconstitutional while Trump’s administration argues that Trump v. Hawaii settled the constitutionality of the proclamation.

The rational-basis issue and whether the court should refer to the reasoning in either Trump v. Hawaii or Kleindienst v. Mandel, which decided that the power to exclude aliens is a power inherent to every sovereign state, were heavily discussed during the arguments. The appellants in this case also had to argue why the Fourth Circuit judges, G. Steven Agee, Paul Victor Niemeyer and Julius Ness Richardson, should view the animus of the travel ban differently than the Supreme Court found in remanding this case and in Trump v. Hawaii. The judges questioned how appellants could overcome the the low rational basis bar required of the government to prevent his case being dismissed. Appellants argued that they have sufficient evidence of animus to at least move to discovery, and appellees argued that any animus evidence was not plausible enough to move forward with the case.

Trump also announced last week that he planned to add several more countries to the ban.