The source of the bad data was a Department of Homeland Security tool called the Systematic Alien Verification for Entitlements, or SAVE.

Once used mostly to check immigrants’ eligibility for public benefits, SAVE has undergone a dramatic expansion over the last year at the behest of President Donald Trump, who has long falsely claimed that millions of noncitizens lurk on state voter rolls, tainting American elections.

Why is the Department of Homeland Security in charge of a program to check if people can get benefits?