If the court hands Trump a victory in the case in June, when it is expected to rule, it will be a sign that a majority of the justices are reluctant to probe the controversial and often conflicting statements and tweets by the unorthodox president and his advisers when scrutinizing the legality of his actions. It would demonstrate a preference for a plain text reading of the law without questioning the executive’s motives.

The president’s executive order faced a losing streak in multiple lower courts since he issued it a week after taking office, forcing the White House to change the order’s wording two times. Trump grumbled on Twitter that the later versions were “watered down” and “politically correct,” and attacked the courts that ruled against him.

Kennedy, who has occasionally sided with the court’s liberals in high-profile cases, repeatedly expressed concern about the court inserting itself into a president’s national security decision-making, suggesting it was not its place to do so. He also argued against the courts giving Congress the power to usurp presidential authority on security-related immigration restrictions.

“You want the president to say, ‘I’m convinced in six months we’ll have a safe world’?” Kennedy retorted.

Those concerns were echoed by his conservative colleagues, including Roberts, who suggested that second-guessing the president’s national security decisions would lead to a slippery slope that could render the president powerless.

Neal Katyal, who argued against the ban on behalf of the state of Hawaii and a Muslim group, attempted to assuage justices’ concerns about overruling the president on a national security matter — a rare action for the Supreme Court.

“We’re not asking you to second-guess national security judgment at all,” Katyal said.

Katyal argued that the court should decide whether a “reasonable observer” would look at the president’s statements about Muslims and the travel ban and decide the executive order was designed to disparage a certain religion.

(On the campaign trail, Trump said he wanted to ban all Muslims from entering the country because America has “problems” with them. He said he would consider closing mosques in the United States and falsely claimed that he saw thousands of Muslims in New Jersey cheering during the Sept. 11 attacks. He called Muslims “sick people.” Seven days after taking office, he issued the first version of the travel ban.)

But Trump’s lawyer, Solicitor General Noel Francisco, said any comments the president made on the stump should be entirely “out of bounds” in the Supreme Court. The oath of office offers a “fundamental transformation” of a private citizen into the president, he argued.

Francisco also said that because the ban does not affect the majority of the world’s 2 billion Muslims, it cannot be seen as targeting the religion.

“This is not a so-called Muslim ban. If it were, it would be the most ineffective Muslim ban that one could possibly imagine,” Francisco said.

Kennedy, even while appearing supportive of the president’s broad national security mandate, seemed skeptical of the government’s claim that campaign statements have no legal weight once a candidate is sworn into office.

“Suppose you have a local mayor and, as a candidate, he makes vituperative, hateful statements,” Kennedy said. “He’s elected, and on day two, he takes acts that are consistent with those hateful statements. Whatever he said in the campaign is irrelevant?”

Francisco answered yes.

Justices Elena Kagan and Sonia Sotomayor, of the court’s liberal wing, also presented stinging and pointed hypotheticals of a hateful politician during the oral argument, asking the lawyers whether they should ignore a background of bigotry when evaluating policy.

“So let’s say in some future time a president gets elected who is a vehement anti-Semite and says all kinds of denigrating comments about Jews and provokes a lot of resentment and hatred over the course of a campaign,” said Kagan.

Later, that president asks his staff to craft a proclamation banning travel from Israel, Kagan said. Would that be legal?

Francisco answered it was a “tough hypothetical” but that it probably would be, as long as there were real national security concerns underlying the decision to ban Israelis. Francisco said that would be hard for him to imagine.

“This is an out-of-the-box kind of president in my hypothetical,” Kagan said pointedly, drawing laughter from the usually somber court audience.

“We don’t have those, your honor,” the solicitor general answered back.

Sotomayor pressed Francisco to explain whether a different hypothetical president is allowed to tell his staff “I want to keep out Jews,” and then ask them to craft an executive order accomplishing that.

Francisco conceded that in that case, the executive order would likely not pass muster.