Trump’s executive order, signed in January, seeks to deny citizenship to children who are born to people who are living in the U.S. illegally or temporarily. It is part of the hard-line immigration agenda of the president, who has called birthright citizenship a “magnet for illegal immigration.”

In 1898, the Supreme Court ruled that the children of immigrants who were born in the United States had the right to citizenship—even if their parents weren’t citizens themselves. This is Wong Kim Ark’s story.

In last month’s decision limiting one judicial tool, universal injunctions, the court seemed to invite lower courts to use class actions as an alternative.