In immigration courts, U.S. lawyers have filed thousands of requests to dismiss asylum cases and force people to pursue asylum elsewhere.

© Adam Gray for The New York Times

Hundreds of people had rallied for the family in New York City after they were separated by Immigration and Customs Enforcement agents in November.

In a previously undisclosed partnership, the Transportation Security Administration and Immigration and Customs Enforcement are sharing data to identify passengers on upcoming flights whom ICE can arrest. Our reporter Hamed Aleaziz, who learned of this partnership, describes what to know about it and the ICE arrests that have followed.