I understand the process of tracking migration and visitation while finding a balance for security of citizens is complex and not easy however I do think these new restrictions are unfortunate.
Most often what happens next is these countries will enforce similar new restrictions and the result is limited travel in the world. Surely these travel restrictions and complications will affect global initiatives for many groups and organizations.
U.S. Tightens Visa-Waiver Program in Bid to Deter Militants – The New York Times
The move is intended to prevent European radicals from traveling to the United States to carry out an attack similar to the one in Paris.
Source: U.S. Tightens Visa-Waiver Program in Bid to Deter Militants – The New York Times