For decades, the U.S. has had a system to record who comes into the country, but tracking who actually leaves has been much harder. This bill matters because it pushes for a high-tech solution to close that 'exit' loop, which is a major issue in the debate over illegal immigration and national security.

If this becomes law, it could lead to more facial recognition scans at airports and borders. Voters who care about border security will see this as a way to ensure the government is following through on its promises, while those concerned about privacy or 'big brother' surveillance will want to watch how the privacy protections and data-sharing agreements with countries like Canada are handled.