ACLU lawyer Omar Jadwat talks to reporters following oral arguments at the U.S. District Court for the District of Maryland on Oct. 16, 2017.
A federal judge heard oral arguments Monday over the legality of the Trump administration's latest travel restrictions, pushing the parties for some sort of standard to evaluate the limits of presidential authority.

In a hearing before the U.S. District Court for the District of Maryland, Judge Theodore Chuang pressed government lawyer Hashim Mooppan and the opposing lawyers, Omar Jadwat of the American Civil Liberties Union, Justin Cox of the National Immigration Law Center, Gadeir Abbas of the Council on American-Islamic Relations and Mark Mosier of Covington & Burling, on when and how the president exceeds his authority under immigration law.

Chuang also wanted to know at what point the president could make a national security-related decision on immigration that the plaintiffs would not consider discriminatory based on President Donald Trump's prior remarks.

The four opposing counsel split their time Monday, arguing on behalf of individual and organizational plaintiffs in three separate lawsuits that asked Chaung to issue an injunction against Trump's Sept. 24 proclamation. The proclamation indefinitely limits immigration from eight countries, six of which are majority-Muslim.

“Other than the fact that this is arguably more broad than anything that's been done before, what tells me that this has gone way over the line, legally?” Chuang asked Cox.

Cox and others groups challenging the proclamation want Chuang to enjoin Trump's second travel ban executive order on the grounds that it was likely motivated by animus against Muslims. The Supreme Court last month dismissed a previous challenge as moot and vacated that ruling because the previous order expired, but noted it made no finding on the merits of that case.

The government contends a section of the Immigration and Nationality Act gives the president broad authority to make immigration decisions, especially when those decisions are based on nationality security or foreign policy concerns. Throughout the hearing, Chuang pushed for answers about the limits on this authority.

Mooppan said that should the president try to make changes for domestic policy reasons, such as determinations about work visas, that could potentially run afoul of the INA because it's Congress that makes and changes immigration laws. But Mooppan also maintained there are no limits courts can impose on the president's authority under the statute when it comes to foreign policy and national security decisions as they fall “squarely” within the president's purview.

Cox argued that simply providing a foreign policy justification for the orders doesn't satisfy the judge's request for a limit because the government could just make up a justification anytime it wants to skirt the law in the immigration context.

“That's no limit at all,” Cox said of the government's argument.

Jadwat said that because Trump repeatedly said he wanted a ban on Muslim immigration during the presidential campaign, and made other comments about wanting to strengthen the first and second travel ban executive orders, Trump is clearly determined to block Muslims from entering the country.

Again, Chuang asked for a bright-line test. This time, the judge wanted to know what travel restrictions the government could issue for national security reasons that the plaintiffs wouldn't sue him over, given that they've challenged the past three executive orders.

“If [the Sept. 24 proclamation] does not cure the issues that you raised last time, what would the government have to do to demonstrate that they have [done so]?” Chuang asked. The judge noted that this time, the government conducted a global review of vetting procedures and the Department of Homeland Security issued a report recommending the restrictions.

Jadwat said it was difficult to answer the question given the president said he wanted to ban Muslims and later, that he would do so legally by imposing national origin restrictions. Jadwat added that even before the DHS issued the report, the president tweeted he wanted a stronger travel ban.

The government maintains the proclamation is neither discriminatory in its language nor effect.

The restrictions are set to go into effect Oct. 18, though Chuang did not indicate when he would make a decision. A federal judge in Hawaii, Derrick Watson, is also considering a separate request to block the Sept. 24th restrictions, and could make a ruling at any time.

The first travel ban executive order, issued in January, was quickly blocked by a federal court in Washington state. That court is also considering a revived challenge to the restrictions, as is a court in Washington, D.C., though those cases are on slower schedules than Hawaii or Maryland.