One of the first moves President Trump made after taking office in 2017 was to implement what became known to critics as his “Muslim ban,” a policy that restricted people from certain countries from traveling to the United States. President-elect Joe Biden has pledged that one of his first actions after taking office on Jan. 20 will be to eliminate that ban.

Trump, who had campaigned in 2016 with pledges to monitor American Muslims and keep other Muslims out of the United States, introduced the ban a week after taking office. It barred the entry of foreign nationals from seven Muslim-majority countries — Iran, Iraq, Libya, Somalia, Sudan, Syria and Yemen — and suspended all refugee arrivals. The ban is now in its third iteration after numerous court challenges, and it prohibits entry to most people from Iran, Libya, North Korea, Somalia, Syria and Yemen, as well as immigrants from Eritrea, Kyrgyzstan, Myanmar and Nigeria, and select people from Tanzania and Venezuela.

The administration ultimately justified the ban by saying it applies to countries that do not adequately share the level of intelligence the United States needs to properly vet their citizens. National security experts have noted that the administration has presented scant evidence of terrorism threats originating with citizens of any of the banned countries who obtained visas.

Biden, who, like others in the Democratic Party, thinks the ban serves a racist agenda rather than a national security purpose, has said that such bans are “morally wrong,” and his administration plans to do away with them within his first 100 days in office, meaning the U.S. government posture could change by spring.

The Washington Post's Supreme Court reporter Robert Barnes explains the justices' 5-4 decision June 26 to uphold President Trump's travel ban. (Joyce Koh/The Washington Post)

“The Trump administration’s anti-Muslim bias hurts our economy, betrays our values, and can serve as a powerful terrorist recruiting tool,” the Biden campaign website says. “Prohibiting Muslims from entering the country is morally wrong, and there is no intelligence or evidence that suggests it makes our nation more secure. It is yet another abuse of power by the Trump administration designed to target primarily black and brown immigrants. Biden will immediately rescind the ‘Muslim bans.’ ”

The current iteration of the ban still primarily affects Muslims, and immigration lawyers and advocates estimate that tens of thousands of people have had their visa applications denied outright or sit idle for months or years in a bureaucratic purgatory known as “administrative processing.”

Immigration advocates and Biden allies said in interviews that they are confident that Biden will rescind the ban on his first day in office.

“The Muslim travel ban, I think, will be one of the first things,” said Sen. Richard J. Durbin (D-Ill.), who has spoken with Biden’s campaign and transition team about the president-elect’s immigration priorities. “Psychologically, it is such an important move.”

Because the ban was introduced via executive order, Biden can undo it in the same way, experts said. New guidance could go to consular officers and U.S. Customs and Border Protection officials in a matter of days.

But it probably will take much longer for that policy shift to yield actual travel visas for people hoping to come to the United States.

Gadeir Abbas, a staff attorney for the Council on American-Islamic Relations (CAIR) who helped pursue court cases challenging the ban, said that getting logistical support back up and running by dismantling the network of bureaucratic obstacles the Trump administration erected will take time. He said visa processing via the State Department and petition processing within U.S. Citizenship and Immigration Services “has been effectively gutted.”

“Its character has been altered in ways that will not be instantaneously unwound by revoking the executive order,” Abbas said.

Those who support the ban say its revocation will expose the United States to fresh national security threats and will exponentially expand the vetting burden for intelligence officials, which could amplify processing delays.

“Changing the guidance would be the work of just a few days,” said one Department of Homeland Security official who thinks the Trump administration protocols serve an important purpose and who spoke on the condition of anonymity because they were not authorized to speak publicly. “But because the lack of access to foreign criminal and terrorist databases that the Executive Order was designed to offset would remain, the workload for those doing the actual screening before the visas could be issued would likely greatly increase because there would suddenly be so many more people applying for visas who would require more careful scrutiny.”

Abbas and other attorneys who represented plaintiffs who were separated from loved ones, jobs, college courses or medical treatment because of the ban, estimate that tens of thousands of people were either rejected outright because of the policy or are awaiting the outcome of processing or waiver appeals. An untold number of others never applied for visas that they otherwise would have sought, Abbas and other lawyers said.

“However many visas have been denied based on the Muslim ban, and however many waivers have been denied or granted, I think won’t really capture the total number of folks who have been affected by the Muslim ban,” he said.

A backlog of visa applications in administrative limbo will need to be processed and either denied or approved, immigration experts say.

“There’s a large group of people who would have applied for visitor visas, student visas, a variety of other temporary visas, and they’re probably going to start from scratch,” said Sirine Shebaya, executive director of the National Immigration Project of the National Lawyers Guild. “So people who might have otherwise gotten a multiple-entry visitor visa I think are probably at step zero.”

And then there are others who were rejected because of the ban who may want to try again, or who the Biden administration may decide are entitled to an automatic appeals process.

Many visa denials under the Trump administration referenced the president’s policy as the reason, Shebaya noted, adding: “So for the people who were denied the visa altogether, I think there’s a question of how the Biden administration is going to deal with those.”

Advocates for immigrants and refugees note that Trump did not pioneer lengthy vetting protocols — or the scrutiny applied to those traveling from Muslim countries. Strict preexisting screening means that even without the ban, processing immigrant applications, for example, could take years.

“Even if you undo all the damage to the immigration and visa system that the Trump administration very creatively inflicted over the course of four years, what you’re left with is a pre-Trump immigration system that still systematically discriminated against Muslims,” Abbas said. “It was always the case that if you were from a Muslim-majority country, your immigration application would not be treated the same way.”