The Citizenship Clause, ratified in 1868 after the Civil War, was included to ensure that formerly enslaved people would be citizens. It effectively overturned the notorious Dred Scott decision, in which the Supreme Court held that Black people, no matter their status, were not citizens.

The Justices on the Supreme Court wrestled on Thursday with a high-stakes case involving birthright citizenship that’s poised to shape both the Trump Administration’s immigration policy and its attempts to expand presidential power.