The United States administration has asked the Supreme Court to revive its controversial ban on travellers from six Muslim-majority countries, despite repeated setbacks in the lower courts that found it was discriminatory.
President Donald Trump issued an executive order on March 6, barring people from Libya, Iran, Somalia, Sudan, Syria and Yemen for 90 days while the government put in place stricter visa screening.
Last week, the federal appeals court in Richmond, Virginia, maintained a block on the ban, stating that Trump's travel policy was rooted in "intolerance".
A similar ruling against Trump's policy from a Hawaii-based federal judge is still in place and will be reviewed by the 9th Circuit Court of Appeals.
"We have asked the Supreme Court to hear this important case and are confident that President Trump's executive order is well within his lawful authority to keep the nation safe and protect our communities from terrorism," Sarah Isgur Flores, spokeswoman for the Department of Justice, said.
"The president is not required to admit people from countries that sponsor or shelter terrorism until he determines that they can be properly vetted and do not pose a security risk to the United States."
The American Civil Liberties Union, one of the legal groups challenging the ban, tweeted in response: "We've beat this hateful ban and are ready to do it again."
The National Immigration Law Center also said it was "ready to keep fighting" the "unconstitutional ban".
Many others took to Twitter to express similar views:
At least five votes are needed on the nine-justice court in order to grant a stay. The court has a five-four conservative majority, with Justice Anthony Kennedy - a conservative who sometimes sides with the court's four liberals - the frequent swing vote.
Another of the court's conservatives, Neil Gorsuch, was appointed by Trump this year.
If the government's request is granted, the ban would go into effect, but Peter Matthews, professor of political science at Cypress College, predicted that the Supreme Court would not allow Trump's "discriminatory" order to be reinstated.
"The Supreme Court ruling will be the final say on this idea of equal protection under the law and non-discrimination based on religion," he told Al Jazeera from Los Angeles.
"It's a very important basic principle of America, and I think even the conservative justices, at least one or two of them … will side with the argument that liberty is so important that you cannot ban a group of people just because of their faith in a blanket way - it's absolutely unconstitutional, in my view."
Trump issued a first travel ban order on January 27, just a week after taking office. It led to chaos and protests at airports before it was blocked by courts.
The second order was intended to overcome the legal issues posed by the original ban, but it was blocked by judges before it could go into effect on March 16.
During the campaign, Trump called for a "total and complete shutdown of Muslims entering the United States."
His administration has argued that the travel ban is needed to prevent "terrorism" in the US, but the ACLU and several other groups, as well as law experts, scholars and activists, say that Trump's statements on the campaign trail and statements from his advisers since he took office make clear that the intent of the policy is to ban Muslims.
"During his campaign, Trump promised a ban on Muslims entering the country. This is discrimination on the basis of religion, which is unconstitutional," Danielle McLaughlin, a constitutional law scholar, told Al Jazeera in March.
Source: Al Jazeera and news agencies