The article explores why some local law enforcement agencies in the US work with federal immigration authorities. It found that these decisions are not based on crime rates, as some believe, but on political factors like the county's political party makeup and the number of Hispanic/Latino residents. Counties with more Republicans and a larger Hispanic/Latino population are more likely to cooperate with federal immigration authorities. This cooperation is seen as a way for county officials to handle the increasing costs of detaining undocumented immigrants.