ICE agents search the passenger of a truck as they arrest both him and the driver during a traffic stop in February in Robbinsdale, Minn. Almost a quarter of ICE arrests in recent months have been "collateral," a category that has raised legal questions, rather than "targeted" arrests based on preexisting warrants or removal orders. (Photo by Nicole Neri/Minnesota Reformer) A quarter of immigration arrests since August were labeled by U.S. Immigration and Customs Enforcement as “collateral,” a type of arrest and detention that’s been challenged in court as an end run around civil rights. Public outrage and lawsuits over the arrests may be tamping down the large-scale sweeps that foster them, but tens of thousands were arrested this way between August and early March. Immigration arrests are usually based on warrants obtained ahead of time, showing either a removal order from immigration court or evidence of a crime or charge that makes the person subject to deport...