Now, after the courts have blocked the order and the President has issued a revised edition, the Department of Justice has gone to the Supreme Court.
Has the President finally found a court that will endorse the legal underpinnings of the travel ban and allow it to go into effect?
In legal briefs filed at 10:51 p.m. ET Thursday night, acting Solicitor General Jeffrey B. Wall asked the court for two things: allow the ban to go into effect now and hear arguments concerning its legality next fall.
Many believe the justices will ultimately want to review the lower court opinions that struck down a major initiative of the Executive Branch. But would they allow the ban to go into effect immediately, before they even have the opportunity to hear arguments?
As the court contemplates the government's requests -- and the country and much of the world waits -- legal experts are in overdrive exploring potential off ramps for the justices. As usual, Justice Anthony Kennedy could be the decider-in-chief.
Complicating efforts could be the President's own words. Trump on Monday emphatically referred to his executive order
on immigration as a "travel ban" and said his Justice Department should not have submitted a "watered down, politically correct version" to the Supreme Court.
Trump's suggestion that changes to the ban were due to political correctness could hamper his administration's legal argument that the executive order did not target Muslims. As a candidate, Trump called for a "total and complete shutdown" of Muslim immigration to the United States, and Justice Department lawyers have gone to great lengths to avoid calling it a "travel ban" in court, referring to it as a "temporary pause" or simply "the executive order."
Should the ban go into effect immediately?
The first request the government makes -- asking for the court to put a hold on the lower courts' injunctions -- might be an uphill climb.
One factor the justices will consider is whether "irreparable harm" would result from a denial of the government's request, keeping the lower courts' injunctions on the ban in place.
Late Friday afternoon, the justices asked the challengers to respond to the government's petition.
The challengers are likely to point out that since the revised travel ban was blocked before it could ever go into effect, there can't be any "irreparable harm" in maintaining the status quo.
That might doom the government's application.
But what if the court did grant the government's request and allowed the ban to go into effect now? That could unleash an unusual circumstance because of the travel ban's unique time limitation.
The ban suspends entry for 90 days for those seeking entry from six Muslim-majority countries. So, if the court allows it to go into effect immediately, by the time the justices hear the case next fall, the ban will have expired.
"At that point, the case may very well be moot," wrote
Leah Litman, an assistant professor of law at University of California Irvine School of Law.
Easy way out?
Some believe the Supreme Court might be able to find a way to defuse the issue that is tangled up in two slightly different injunctions that have been issued by the Fourth Circuit Court of Appeals and by a district court judge under the jurisdiction of the Ninth Circuit Court of Appeals.
In essence, the justices would respond to the government's stay application by narrowing the scope of the injunctions, allowing some of the challenged provisions of the ban go into effect while upholding a block on the most contentious aspect: the section that actually suspends travel.
Harvard Law School Professor Mark Tushnet floated the idea, calling it an "easy out" for the court.
"The case will then almost certainly be moot by the time it's argued, and all that would be left would be to clean things up, presumably by directing that whatever injunctions are still in effect should be vacated," he posited
on the Balkinization blog, which discusses legal matters.
The Kennedy factor
But what if the court does not take Tushnet's off ramp and eventually digs into the merits of the case? Kennedy could, as usual, be a critical vote.
Challengers say the order is motivated by religious animus in violation of the Establishment Clause of the Constitution. The President's intent, they say, is evident from statements he made on the campaign trail referring to a so-called "Muslim Ban."
In its opinion that upheld a halt of the ban, the Fourth Circuit Court of Appeals issued a ringing endorsement of that argument.
"Then-candidate Trump's campaign statements reveal that on numerous occasions, he expressed anti-Muslim sentiment, as well as his intent, if elected, to ban Muslims from the United States."
In briefs filed with the Supreme Court, however, Wall insists that the courts were wrong to look at Trump's campaign statements.
Instead, he argues, they need to look only at the face of the order. In doing so, they will find the order is neutral with respect to religion and is necessary to support national security determinations.
"It is religion-neutral in operation," Wall wrote. "It draws distinctions among countries based on national-security risks identified by Congress and the Executive (Branch), not religion."
That's where Kennedy could come in play. Would he consider the campaign statements?
Challengers say he would, based upon a concurring opinion he wrote in 2015 in a case called Kerry v. Din.
"Justice Kennedy's separate opinion in that case raised the prospect that courts could look behind the neutral justifications offered by the government in immigration cases in which the plaintiffs claim that the relevant officials acted in bad faith," said CNN contributor Stephen I. Vladeck of the University of Texas School of Law.
"Here, the question is whether Justice Kennedy would look at an array of statements by Candidate Trump, President Trump, and his advisers and surrogates as evidence that the travel ban was in fact motivated by inappropriate anti-Muslim bias," he said.
Not surprisingly, in blocking the order, the Fourth Circuit relied in large part on what Kennedy wrote in Din.
In its opinion, the majority of the Fourth Circuit said: "Kennedy explained that where a plaintiff makes 'an affirmative showing of bad faith' ... courts may 'look behind' the challenged action."
In his legal filings, Wall said the Court of Appeals got it wrong and rested on a "misreading of a statement in Justice Kennedy's concurrence in Din."
Wall said, in essence, that Kennedy was not endorsing a "wide-ranging search for pretext."
End of the term
The court is likely to act on the government's requests sometime in June during the final month of the current term. The travel ban has turned a sleepy term into a potential blockbuster.
As the justices race to finish opinions from this term, they are also considering hot button issues for the next term, including cases on the Second Amendment, religious liberty and even a follow-up to the same-sex marriage opinion from 2015.
Now, the travel ban is a part of that list.