Donald Trump’s executive order to temporarily ban nearly all travellers from seven Muslim-majority countries more than a week ago caused massive protests and multiple lawsuits, outrage from civil rights groups and tens of thousands of people had their visas revoked.

It was also the only executive order on the White House website whose title was written in capital letters.

"PROTECTING THE NATIONAL FROM FOREIGN TERRORIST ENTRY INTO THE UNITED STATES" generated plenty of headlines.

But a smaller section of the order may have been missed, and it could be of critical importance.

Under Section four, it reads there will be "development of a uniform screening standard and procedure" and suggests but does not mandate interviews, and thorough back-ground checks.

Legal experts argue this phrase could affect every foreign visitor to the US, including diplomats, corporate transfers, foreign employees and even tourists who are trying to visit Disney World.

"It would basically shut down tourism," Stephen Legomsky, the former chief counsel for US Citizenship and Immigration Services during the Obama administration, told Politico.

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As stated in the order, the "mechanism" to determine if the visitor has "malicious intent" is not specified.

The section also requires that all visitors and immigrants would be a "positively contributing member of society", but again, this is left vague.

Anastasia Tonello, first vice president of the American Immigration Lawyers Association, said those two specifications struck her as odd.

"There are no criteria under the existing statute that you would have to be a positive contributing member to society, but they [the government] do have broad discretion and they can deny people without giving a reason," she told The Independent.

She added that she had been very worried about the lack of clarity around dual nationality, and that was only clarified this week that the ban would not apply there.

The US already heavily vets immigrants.

Syrian refugees, of which Mr Obama took in around 12,500 last year, underwent a process that lasted at least two years. No Syrian immigrant has been charged with the intent to, or has carried out, a terrorist attack on US soil in the last four decades, a report from the Cato Institute found.

The executive order has already come under fire for being rolled out hastily and poorly, with no guidance to airports and airlines who had to deal with incoming visitors and immigrants from the seven countries who were in the air when Mr Trump banned them from the US.

Protestors rally at JFK Airport against Muslim immigration ban Show all 20 1 /20 Protestors rally at JFK Airport against Muslim immigration ban Protestors rally at JFK Airport against Muslim immigration ban jfk-protest-muslim-ban-1 Protestors rally during a demonstration against the Muslim immigration ban at John F. Kennedy International Airport on January 28, 2017 in New York City. President Trump signed the controversial executive order that halted refugees and residents from predominantly Muslim countries from entering the United States. Getty Protestors rally at JFK Airport against Muslim immigration ban jfk-protest-muslim-ban-2 Protestors rally during a protest against the Muslim immigration ban at John F. Kennedy International Airport on January 28, 2017 in New York City. President Trump singed the controversial executive order that halted refugees and residents from predominantly Muslim countries from entering the United States. Stephanie Keith/Getty Protestors rally at JFK Airport against Muslim immigration ban jfk-protest-muslim-ban-3 Protestors rally during a protest against the Muslim immigration ban at John F. Kennedy International Airport on January 28, 2017 in New York City. President Trump singed the controversial executive order that halted refugees and residents from predominantly Muslim countries from entering the United States. Stephanie Keith/Getty Protestors rally at JFK Airport against Muslim immigration ban jfk-protest-muslim-ban-4 SAN FRANCISCO, CA - JANUARY 28: Demonstrators hold signs during a rally against a ban on Muslim immigration at San Francisco International Airport on January 28, 2017 in San Francisco, California. President Donald Trump signed an executive order Friday that suspends entry of all refugees for 120 days, indefinitely suspends the entries of all Syrian refugees, as well as barring entries from seven predominantly Muslim countries from entering for 90 days. Stephen Lam/Getty Protestors rally at JFK Airport against Muslim immigration ban jfk-protest-muslim-ban-5 A crowd of protesters gathers outside of the Brooklyn Federal Courthouse as a judge hears a challenge against President Donald Trump's executive ban on immigration from several Muslim countries, on January 28, 2017 in Brooklyn. The judge issued an emergency stay on part of Trump's executive order, ruling that sending refugees stopped at U.S. airports back to their countries would be harmful. Yana Paskova/Getty Protestors rally at JFK Airport against Muslim immigration ban jfk-protest-muslim-ban-6 Protestors rally during a demonstration against the new immigration ban issued by President Donald Trump at John F. Kennedy International Airport on January 28, 2017 in New York City. President Trump signed the controversial executive order that halted refugees and residents from predominantly Muslim countries from entering the United States. Stephanie Keith/Getty Protestors rally at JFK Airport against Muslim immigration ban jfk-protest-muslim-ban-7 NEW YORK, NY - JANUARY 28: Protestors rally during a demonstration against the new immigration ban issued by President Donald Trump at John F. Kennedy International Airport on January 28, 2017 in New York City. President Trump signed the controversial executive order that halted refugees and residents from predominantly Muslim countries from entering the United States. Stephanie Keith/Getty Protestors rally at JFK Airport against Muslim immigration ban jfk-protest-muslim-ban-8 Protestors rally during a demonstration against the new immigration ban issued by President Donald Trump at John F. Kennedy International Airport on January 28, 2017 in New York City. President Trump signed the controversial executive order that halted refugees and residents from predominantly Muslim countries from entering the United States. Stephanie Keith/Getty Protestors rally at JFK Airport against Muslim immigration ban jfk-protest-muslim-ban-9 NEW YORK, NY - JANUARY 28: Protestors rally during a demonstration against the Muslim immigration ban at John F. Kennedy International Airport on January 28, 2017 in New York City. President Trump signed the controversial executive order that halted refugees and residents from predominantly Muslim countries from entering the United States. (Photo by Stephanie Keith/Getty Images) Getty Images Protestors rally at JFK Airport against Muslim immigration ban jfk-protest-muslim-ban-10 NEW YORK, NY - JANUARY 28: Protestors rally during a demonstration against the Muslim immigration ban at John F. Kennedy International Airport on January 28, 2017 in New York City. President Trump signed the controversial executive order that halted refugees and residents from predominantly Muslim countries from entering the United States. (Photo by Stephanie Keith/Getty Images) Getty Images Protestors rally at JFK Airport against Muslim immigration ban jfk-protest-muslim-ban-11 NEW YORK, NY - JANUARY 28: Protestors rally during a demonstration against the Muslim immigration ban at John F. Kennedy International Airport on January 28, 2017 in New York City. President Trump signed the controversial executive order that halted refugees and residents from predominantly Muslim countries from entering the United States. Stephanie Keith/Getty Protestors rally at JFK Airport against Muslim immigration ban jfk-protest-muslim-ban-12 Protestors rally during a demonstration against the Muslim immigration ban at John F. Kennedy International Airport on January 28, 2017 in New York City. President Trump signed the controversial executive order that halted refugees and residents from predominantly Muslim countries from entering the United States. Stephanie Keith/Getty Protestors rally at JFK Airport against Muslim immigration ban jfk-protest-muslim-ban-13 Protestors rally during a demonstration against the Muslim immigration ban at John F. Kennedy International Airport on January 28, 2017 in New York City. President Trump signed the controversial executive order that halted refugees and residents from predominantly Muslim countries from entering the United States. Stephanie Keith/Getty Protestors rally at JFK Airport against Muslim immigration ban jfk-protest-muslim-ban-14 Protestors rally during a demonstration against the Muslim immigration ban at John F. Kennedy International Airport on January 28, 2017 in New York City. President Trump signed the controversial executive order that halted refugees and residents from predominantly Muslim countries from entering the United States. Stephanie Keith/Getty Protestors rally at JFK Airport against Muslim immigration ban jfk-protest-muslim-ban-15 Protestors rally during a demonstration against the Muslim immigration ban at John F. Kennedy International Airport on January 28, 2017 in New York City. President Trump signed the controversial executive order that halted refugees and residents from predominantly Muslim countries from entering the United States. Stephanie Keith/Getty Protestors rally at JFK Airport against Muslim immigration ban jfk-protest-muslim-ban-16 Protestors rally during a demonstration against the Muslim immigration ban at John F. Kennedy International Airport on January 28, 2017 in New York City. President Trump signed the controversial executive order that halted refugees and residents from predominantly Muslim countries from entering the United States. Stephanie Keith/Getty Protestors rally at JFK Airport against Muslim immigration ban jfk-protest-muslim-ban-17 NEW YORK, NY - JANUARY 28: Protestors rally during a protest against the Muslim immigration ban at John F. Kennedy International Airport on January 28, 2017 in New York City. President Trump singed the controversial executive order that halted refugees and residents from predominantly Muslim countries from entering the United States. Stephanie Keith/Getty Protestors rally at JFK Airport against Muslim immigration ban jfk-protest-muslim-ban-18 Protestors rally during a protest against the Muslim immigration ban at John F. Kennedy International Airport on January 28, 2017 in New York City. President Trump singed the controversial executive order that halted refugees and residents from predominantly Muslim countries from entering the United States. Stephanie Keith/Getty Protestors rally at JFK Airport against Muslim immigration ban jfk-protest-muslim-ban-19 Protestors rally during a protest against the Muslim immigration ban at John F. Kennedy International Airport on January 28, 2017 in New York City. President Trump singed the controversial executive order that halted refugees and residents from predominantly Muslim countries from entering the United States. Stephanie Keith/Getty Protestors rally at JFK Airport against Muslim immigration ban jfk-protest-muslim-ban-20 Passengers wait in line to check in at the American Airlines terminal at JFK International Airport August 10, 2006 in the Queens borough of New York City. British authorities arrested 21 people and halted a anallegedly terrorist plot to use liquid explosives concealed in carry-on luggage to blow up airliners traveling between Britain and the U.S. Homeland Security chief Michael Chertoff said that the plot appeared to be directed at U.S. carriers flying out of Heathrow. such as United Airlines, American Airlines, Continental Airlines. Stephen Chernin/Getty

Students, families and even officials were caught in the ban - an Iraqi translator who had worked for the US for years and whose family lived in the US was one of dozens who were placed in handcuffs when their flight landed.

In 2015, more than 10 million people travelled to the US on a visa, while tens of millions more came without one. Section four of the order calls for the secretary of state, secretary of homeland security, director of national intelligence and the director of the FBI to develop a "uniform procedure" for all of them.

A State Department official said: "Working closely with the Department of Homeland Security, we are implementing the Executive Order. We will announce any changes affecting travellers to the United States as soon as that information is available."

The government agencies are currently trying to navigate the ruling as to how it applies to the seven countries in the order - Syria, Iraq, Iran, Somalia, Sudan, Libya and Yemen.

They will now also have to deal with a lawsuit from Washington’s Attorney General Bob Ferguson, which judge James Robart ruled in favour of, which essentially blocks the Muslim ban nationwide.

"No one is above the law," Mr Ferguson said. "Not even the President."

The Justice Department quickly responded to say it would implement an emergency stay of the order, and Mr Trump said the ruling was "ridiculous".

Section four of the original order has not laid out a timeline for the new uniform procedure, but has asked the secretary of homeland security to submit three reports, within 60 days, 100 and 200 days, on the departments’ progress.

The executive order was also applied to visa and green card holders from the seven countries - an issue that Mr Trump’s adviser Steve Bannon reportedly pushed for.