WASHINGTON (Reuters) - The fate of President Donald Trump’s order to ban travelers from six predominantly Muslim nations, blocked by federal courts, may soon be in the hands of the conservative-majority Supreme Court, where his appointee Neil Gorsuch could help settle the matter.

After the Richmond-based 4th U.S. Circuit Court of Appeals declined on Thursday to lift a Maryland federal judge’s injunction halting the temporary ban ordered by Trump on March 6, Attorney General Jeff Sessions said the administration would appeal to the Supreme Court.

A second regional federal appeals court heard arguments on May 15 in Seattle in the administration’s appeal of a decision by a federal judge in Hawaii also to block the ban. A ruling by the 9th U.S. Circuit Court of Appeals is pending.

The Justice Department has not made clear when the administration would make its formal appeal or whether it would wait for the 9th Circuit ruling before appealing.

If they take it up, the justices would be called upon to decide whether courts should always defer to the president over allowing certain people to enter the country, especially when national security is the stated reason for an action as in this case. They also would have to decide if Trump’s order violated the U.S. Constitution’s bar against the government favoring one religion over another, as the ban’s challengers assert.

Gorsuch’s April confirmation by the Republican-led Senate over Democratic opposition restored the court’s 5-4 majority, which means that if all the conservative justices side with the administration the ban would be restored regardless of how the four liberal justices vote.

During his Senate confirmation hearing, Gorsuch was questioned about Trump’s criticism of judges who ruled against the ban. Gorsuch avoided commenting on the legal issue, saying only that he would not be “rubber stamp” for any president.

While the justices could decide in the coming weeks whether to hear the case, they likely would not hold oral arguments until late in the year, with a ruling sometime after that. A final resolution may not come until perhaps a year after Trump issued the executive order.

The justices are not required to hear any case, but this one meets important criteria cited by experts, including that it would be the federal government filing the appeal and that it involves a nationwide injunction.

A picture of the travel advisory page of Qatar Airways advising passengers bound for the United States from seven newly banned majority Muslim countries that they need to have either a U.S. green card or diplomatic visa, January 28, 2017 in London, Britain. Picture taken January 28, 2017. REUTERS/Russell Boyce

The administration could file an emergency application seeking to put the order into effect while the litigation on its legality continues. At least five justices must agree for any such request to be granted.

While the court could split 5-4 along ideological lines, it also is possible some conservative justices could join the liberals in overturning the travel ban, libertarian law professor Ilya Somin of George Mason University said.

“Conservatives in other contexts often take a hard line against any kind of government discrimination (based) on race or religion or the like, even if the motivation may be benign. Also conservatives have concerns about government infringements on religion,” Somin said.

The 4th Circuit said the ban’s challengers, including refugee groups, in the case argued by the American Civil Liberties Union were likely to succeed on their claim that the order violated the Constitution’s prohibition on the government favoring or disfavoring any religion. In the 10-3 ruling, three Republican-appointed judges dissented.

The Republican president’s March 6 order, replacing an earlier Jan. 27 one also blocked by the courts, called for barring people from Iran, Libya, Somalia, Sudan, Syria and Yemen for 90 days while the government implements stricter visa screening. It also called for suspending all refugee admissions for 120 days.

KENNEDY’S REASONING

The travel ban’s challengers may take some comfort from the appeals court ruling’s reliance on a concurring opinion in a 2015 Supreme Court immigration case by Justice Anthony Kennedy, a conservative who sometimes sides with the court’s liberals in big cases.

In the 2015 case, Kennedy wrote that in the immigration context, the government’s actions can be questioned if there is evidence of bad faith.

“As with any opinion by Justice Kennedy, I think the million-dollar question is just what he meant in his concurrence, and this may be a perfect case to find out,” University of Texas School of Law professor Stephen Vladeck said.

In Thursday’s ruling, 4th Circuit Chief Judge Roger Gregory wrote that the plaintiffs had shown there was “ample evidence” of bad faith, which gave the green light to probe whether there were reasons for the order other than the administration’s stated national security rationale.

The administration has argued the temporary travel ban was needed to guard against terrorist attacks. Gregory wrote that the order uses “vague words of national security, but in context drips with religious intolerance, animus, and discrimination.” Trump during the presidential campaign called for a “total and complete shutdown of Muslims entering the United States.”