BYRON TAU and GARANCE BURKE.

Democratic lawmakers are questioning the legality of a U.S. Border Patrol program that uses predictive intelligence to detain drivers for suspicious travel. Sen. Ed Markey of Massachusetts sent a letter Monday to Border Patrol’s parent agency, calling the license plate reader program an “invasive surveillance network.” An Associated Press investigation revealed that the program monitors millions of American drivers to identify and detain people based on travel patterns. Courts have generally upheld license plate reader collection on public roads, but scholars argue it might be unconstitutional under the Fourth Amendment. Other lawmakers echoed Markey’s concerns about the program’s legality.