What is ICE actually doing at the airport?

I arrived at John F. Kennedy International Airport nearly five hours before my domestic flight. This is not my way - usually I roll up to the airport 30 minutes before boarding - but not even I have enough hubris to think that my good luck is more powerful than a partial government shutdown. Congress has yet to pass a bill funding the Department of Homeland Security, meaning thousands of federal employees from TSA to the Coast Guard are working without pay - or, in the case of TSA, calling out of work...