Update: A Federal judge has issued a stay on part of this order, ruling that the 100-200 people currently being detained at U.S. airports cannot be sent back to their home countries. The ruling stopped short of saying travelers had to be allowed in, however, and thus effectively only applies to people currently in the U.S. As best as I can tell, travelers in transit from other countries may still be denied boarding.
Yesterday afternoon, President Trump issued an executive order immediately banning nationals of Iran, Iraq, Sudan, Somalia, Syria, Yemen and Libya from entering or transiting the United States. This is a sweeping ban, and includes not just tourists, but students, guest workers, legal immigrants, refugees, and potentially U.S. green card holders who originally came from one of these seven countries.
As there was no grace period, there are many people who boarded flights with valid documents only to be told upon landing that the law had changed and their paperwork was no longer valid. Others were denied boarding despite having valid visas when they checked in even an hour prior. U.S. lawful permanent residents with long-term visas and green cards are being detained for hours upon arrival, or are stuck in transit.
Leaving politics aside, this is a mess from a travel perspective.
Horribly, refugees who have completed the (lengthy and pervasive) vetting process are being turned away or detained. These are people who have gone through years of investigations and paperwork, and already have housing and jobs lined up in the U.S., and in some cases had family members who traveled earlier in the week that they are now separated from.
Beyond refugees, this order also impacts students and workers on visas, who may now be stranded in another country if they were outside the U.S. or in transit when this order was signed. Universities are advising their foreign students not to leave the country, and Google has recalled their staff from overseas trips.
The Wall Street Journal is reporting the immigration ban “also applies to people who originally hail from those countries but are traveling on a passport issued by any other nation.” In practice, this means if someone is a dual Canadian-Iranian citizen, and was intending to travel to or transit the U.S. on their Canadian passport, they will not be allowed entry.