Protesters converged at JFK airport in New York to rally against Trump's "Muslim ban."

President Donald Trump's shock travel ban slammed shut the borders of the United States for an Iranian scientist headed to a lab in Massachusetts, a Syrian refugee family headed to a new life in Ohio, and a group of high school students hoping to participate later this year in the annual UNIS-UN conference organized by the United Nations International School.
 
With just a few strokes of the pen, Trump on Friday banned citizens from seven Muslim majority countries from entering the US. The move sparked outrage worldwide and US airports were gripped over the weekend by chaos and confusion. Authorities struggled to implement the new order even as hordes of protestors converged on eight large US airports.

 
What does Trump's executive order do?
The order bars people from seven countries — Iran, Iraq, Libya, Somalia, Sudan, Syria and Yemen — from entering the United States for 90 days, while the Trump administration revises immigration screening procedures.
 
Refugee entry into the US has been halted for 120 days, and the entry of Syrian refugees has been stopped indefinitely. Trump's orders, which give priority to Christian refugees, drew sharp criticism, as it establishes a religious test for entering the US and is effectively a “Muslim ban.”
 
US Homeland Security Secretary John Kelly issued a statement clarifying that people from the seven countries who hold green cards as lawful permanent US residents would not be blocked from returning to the US from overseas.

 
What is the aim of the order?
Trump says his "extreme vetting" system will help "keep radical Islamic terrorists out of the United States." 
 
“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,” said Trump.
 
The order speaks of the importance of “detecting individuals with terrorist ties and stopping them from entering the United States,” and gives the September 11, 2001, terrorist attacks as an example of a failure of screening.
 
Oddly, the 9/11 hijackers who carried out the deadly attacks were citizens of Saudi Arabia, the United Arab Emirates, Egypt and Lebanon but the ban does not apply to people from these countries.
 
"I am worried sick about being able to complete my studies in America. Today, Trump's order targets seven Muslim countries. Tomorrow it could very well be my country on Trump's banned list," said Omar Almasi, an engineering student from Saudi Arabia enrolled at Cooper Union for the Advancement of Science and Art, in New York.
 
"This has created so much uncertainty for students like me from Saudi Arabia and the rest of the Muslim world," added Almasi who joined thousands of New Yorkers in Battery Park in New York to decry Trump’s executive order as unconstitutional.
 
Saudi students like Omar Almasi supported by the generous $6 billion King Abdullah Scholarship Fund have made a beeline for US universities. According to the Open Doors report, Saudi Arabia ranked third after China and India in sending the highest number of international students to the US in the 2015-2016 academic year.

During the campaign, Trump proposed “a total and complete shutdown of Muslims entering the US.” He later amended his proposal and emphasized the need for a “proven” vetting mechanism and said that he would bar immigrants from countries that have been “compromised by terrorism.”

President Trump’s chief of staff, Reince Priebus said on Sunday on Meet the Press that the seven countries facing the travel ban were deemed countries of concern by Congress and former President Barack Obama’s administration.


Taking a leaf out of Bush's playbook
Trump is actually taking a leaf out of former US president George W Bush’s 9/11 playbook. In the wake of the 2001 terror attacks, the Bush administration implemented a series of critical — and sometimes controversial — immigration policy measures to respond to future threats of terrorism. Since all 19 terrorists who attacked the US that September morning were Muslims, acute scrutiny in the immediate aftermath of the attacks was focused on Muslims, with broader use of nationality-based screening and enforcement programs.

Under the National Security Entry-Exit Registration System (NSEERS), adult males from 25 predominately Muslim countries known to have a Qaeda presence were required to be fingerprinted, registered and interviewed. According to the Migration Policy Institute, more than 80,000 individuals were interviewed under the program, and over 13,000 were placed in removal proceedings.

However, even the Bush administration’s immigration policies did not blanket ban groups of people from entering America; it only made it that much harder for people from some Muslim countries to enter America by calling for extra screening.

Trump, however, said during the campaign that the US must immediately suspend immigration from any nation that has been compromised by terrorism.


What happens next?
Protestors converged on Sunday afternoon outside the White House, Boston's Copley Square, at Battery Park in Manhattan and at airports in Atlanta, Los Angeles, Washington and Dallas to rally against Trump's immigration policies.
 
Opponents of the "extreme vetting" order say they will launch a legal challenge. Firstly, they are expected to argue that the blanket ban violates the fifth amendment right to due process. Secondly, they will also argue that the order's preferential treatment of Christians over Muslims violates the first amendment on freedom of religion. 
 
Meanwhile, Trump's "Muslim ban" orders are causing headaches for airlines which have begun screening passengers from the seven Muslim-majority countries affected by the travel ban before their departure for the US.

 
Uttara Choudhury is a writer for Forbes India and The Wire. In 1997, she went on the British Chevening Scholarship to study Journalism in the University of Westminster, in London.