Department of Homeland Security Secretary Markwayne Mullin is threatening to tighten restrictions on so-called sanctuary cities that continue to resist federal immigration enforcement efforts.
A proposal under consideration would limit international flights at airports located in sanctuary jurisdictions. An estimated 18 airports across the country could be affected by the policy.
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Newark Liberty International Airport is among the facilities that could face disruptions. About 20,000 Americans arrive at Newark each day, raising concerns that any reduction in operations could have significant effects on global travel.
The airport serves as a major hub for United Airlines, with flights to 97 destinations.
Critics of the proposal warn that if U.S. Customs and Border Protection were to reduce staffing at Newark, the impact could ripple throughout the nation's air transportation system.
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Many travelers rely on Newark to connect to international flights, and the airport also serves as a major global logistics hub, handling the movement of cargo and goods from around the world.
"Any reduction in Customs and Border Protection operations at major U.S. gateway airports threatens to cause unnecessary chaos throughout the nation's air transportation system," the groups said.
Transportation Secretary Sean Duffy has also spoken out against the proposal.
