One of President Donald Trump's most controversial campaign promises was to establish a ban on Muslims entering the United States.

Whether that was the intention of a series of executive orders after he took office is widely debated. But it is clear that the orders impeded the entry of Muslims from some countries, though not from all parts of the world.

About a week after taking office, Trump signed an executive order temporarily suspending immigration from seven Muslim-majority nations and the U.S. refugee program. He indefinitely stopped the entry of Syrian refugees. Courts blocked the order's implementation after states sued alleging it violated constitutional religious liberties.

Trump subsequently signed two more executive orders, each a revision of the previous one, in response to multiple lawsuits challenging their legality. Opponents of the orders said they amounted to a Muslim ban. The Trump administration argued they were not banning immigration based on religion, and were rather driven by national security concerns.

Ultimately, in June 2018, the U.S. Supreme Court upheld the third version of the travel ban in a 5-4 decision. That version restricted the entry of nationals of Iran, Libya, Somalia, Syria, Yemen, North Korea and Venezuela.  

U.S. Supreme Court Chief Justice John Roberts wrote the court's majority opinion, saying Trump's directive was "facially neutral toward religion."

"The proclamation is expressly premised on legitimate purposes: preventing entry of nationals who cannot be adequately vetted and inducing other nations to improve their practices," Roberts wrote. "The text says nothing about religion."

Although five of the seven nations in the order have Muslim-majority populations, "that fact alone does not support an inference of religious hostility," Roberts added, saying that the policy covered 8 percent of the world's Muslim population and was limited to countries previously designated by Congress or other administrations as posing national security risks.

In a dissenting opinion, Associate Justice Sonia Sotomayor pointed out remarks Trump made during his campaign and after the election, including Trump's December 2015 statement calling for "a total and complete shutdown of Muslims entering the United States until our country's representatives can figure out what the hell is going on."

"Taking all the relevant evidence together, a reasonable observer would conclude that the proclamation was driven primarily by anti-Muslim animus, rather than by the government's asserted national-security justifications," Sotomayor wrote.

Trump's order is "not a total ban on people of the Muslim faith," but it does curtail their entry, said Betsy Fisher, policy director for the International Refugee Assistance Project at the Urban Justice Center, which represents refugees in immigration proceedings.

While the majority of people banned under Trump's order are Muslim, "there is little if any evidence indicating that their exclusion protects national security," Ilya Somin, a law professor at George Mason University and an adjunct scholar at the libertarian Cato Institute, wrote after the Supreme Court ruling.

Trump promised a "total and complete shutdown" of Muslims entering the United States. His executive orders accomplished substantially less — ultimately only restricting the entry of people from five Muslim-majority nations.

The Trump administration argues it is not a ban based on religion, but on national security concerns. Many disagree, saying that the executive orders were watered-down versions of Trump's Muslim ban promise. The U.S. Supreme Court in a 5-4 decision upheld Trump's directive.

The motivation behind the orders is widely debated. But what ultimately got through was not the sweeping religious ban that Trump advocated during his presidential primary. We rate this Promise Broken. 

Donald Trump as a presidential candidate called for a ban on Muslims entering the United States, claiming large segments of the population had "great hatred towards Americans." But he also suggested that he wasn't calling for a ban, and then said he wasn't backtracking.

Let's sort out what's happened so far.

Days after a married Muslim couple carried out a deadly shooting attack in San Bernardino, Calif., his team released a statement Dec. 7, 2015, about his proposal.

"Donald J. Trump is calling for a total and complete shutdown of Muslims entering the United States until our country's representatives can figure out what is going on," it said.

Trump said polling and research backed his concerns over Muslims. But polling experts questioned the validity of the poll Trump cited and the center who issued the poll cautioned against generalizations.

Trump tweaked his message in his Republican nomination acceptance speech July 21, 2016: "We must immediately suspend immigration from any nation that has been compromised by terrorism until such time as proven vetting mechanisms have been put in place."

This prompted NBC's Chuck Todd to ask Trump if he was rolling back his stance on banning Muslims.

"I actually don't think it's a rollback. In fact, you could say it's an expansion. I'm looking now at territories. People were so upset when I used the word Muslim. Oh, you can't use the word Muslim. Remember this. And I'm okay with that, because I'm talking territory instead of Muslim," Trump said in an interview aired July 24, 2016.

As president, Trump has signed two executive orders — one in January and a replacement in March — to temporarily halt entry of nationals from several Muslim-majority countries in the Middle East and Africa. His administration said the countries were selected due to their connection to terrorism.

Challenges in courts halted the orders' implementation.

Some Democratic lawmakers have called his orders a Muslim ban, which the Trump administration has repeatedly refuted.

• Trump, Jan. 29: "To be clear, this is not a Muslim ban, as the media is falsely reporting. This is not about religion. This is about terror and keeping our country safe."

• Sean Spicer, Trump's press secretary, Jan. 31: "I think the president has talked about extreme vetting and the need to keep America safe for a very, very long time. At the same time, he's also made very clear that this is not a Muslim ban, it's not a travel ban. It's a vetting system to keep America safe."

• Vice President Mike Pence, Feb. 2: "It's not a Muslim ban. It's not in any way associated with religion."

Trump called for a Muslim ban as presidential candidate. As president, he has denied that his administration has directed a Muslim ban. We rate this promise Stalled.

Donald Trump promised during the primary race that he would halt Muslim immigration to the United States in an attempt to prevent terrorist attacks on American soil.

"Donald J. Trump is calling for a total and complete shutdown of Muslims entering the United States until our country's representatives can figure out what the hell is going on," he said at a December 2015 rally.

In the general election, he changed his position, instead calling for a ban on immigration from regions with a history of terrorism. But Trump hasn't explicitly backed off his Muslim ban proposal, and it's still on his website.

WHY HE'S PROMISING IT

Trump is concerned that foreign Muslims have hostile views of the United States and that the government is unable to thoroughly vet immigrants from conflict areas like Syria.

He made the promise days after a married Muslim couple went on a shooting spree in San Bernardino, Calif., killing 14 people. The husband was born in the United States to Pakistani immigrants, and the wife was a legal immigrant born in Pakistan.

WHAT NEEDS TO HAPPEN

Trump will have broad authority to stop certain groups from immigrating to the United States. Past presidents banned Iranians during the Iran hostage crisis, as well as known communists during the Cold War.

The president gets this authority from the Immigration and Nationality Act of 1952. The law says the president can "suspend the entry of all aliens or any class of aliens."

WHAT'S STANDING IN HIS WAY

Politics likely would block a full Muslim ban. Leaders in both the Democratic and Republican parties criticized the proposal when Trump first floated it. Congress could take away his authority under the Immigration and Nationality Act.

"What was proposed yesterday is not what this party stands for, and more importantly, it's not what this country stands for," said House Speaker Paul Ryan, R-Wis., in a Dec. 8, 2015, press conference.

Experts say it would be difficult to implement a Muslim ban because of the inability to definitively verify someone's religion.

If Trump were to implement a ban on all Muslims, the United States would be the only country to have a religion test at its border.