The Hill reports that the Homeland Security Secretary is:

“drawing up plans” to end the processing of international flights in left-leaning cities, pointing to protests outside an immigration detention center in New Jersey as rationale.

To the extent that the choice of airports in major cities is random with respect to economic conditions (although not to whether the closest city is a vaguely defined “sanctuary city”), this would provide an ideal dataset for examining how cessation of processing would impact city economic conditions. One might think that implementing this policy would have a small effect, adn indeed it might. However, if I think of the multiplier effect of diminished airport activity propagating through reduced employment, as well as reduced hotel and accommodation revenues, I think it would very well be possible to see a significant impact.

Such a natural experiment could be assessed using typical differences-in-differences estimation (see Chapter 13 of Stock and Watson).

Here are some assessments of the likely impact:

Critics said ending the processing of international flights at various airports would cause chaos at airports across the country, forcing airlines to cancel flights and disrupt travel for left- and right-leaning cities that depend on CBP processing at major hubs.

Reuters indicates the cities in question (DoJ designated “sanctuary cities”):

Among these were Boston, Denver, Philadelphia, Chicago, Los Angeles, New York City, Newark, ‌Seattle ⁠and San Francisco.

While some people might welcome a respite from foreign tourists, what is also true is that trade and FDI relies critically on the ability of businesspeople being able to traverse borders easily. So, in case you wanted even costlier and scarcer imports, this is the policy for you.