Estelle, who’s long held permanent resident status in the U.S., is a veteran at navigating the reentry process when she returns from visiting relatives in her native France.

But on her most recent trip through customs in mid-March, officers detained the 57-year-old Lawrence, Kansas, resident for 30 hours, forced her to spend the night in a holding cell on a concrete slab and threatened her with deportation.

Why? Because she acknowledged under questioning by customs officers that she’d once voted in a local election, despite not being a U.S. citizen. A small number of cities in the U.S. allow noncitizens to vote in local elections, but Lawrence is not one of them. Kansas and federal law both require U.S. citizenship to register to vote.