The practice, many legal historians believe, dates to the 1600s and 1700s, with European rulers encouraging migration to the expanding American colonies. Those colonists, though, wanted any of their children born overseas to retain European citizenship. So even as the colonial boundaries shifted “you’re a citizen as long as you’re born within the domain of the king, of the monarch,” said César Cuauhtémoc García Hernández, a law professor at Ohio State University. “But the leg

Soaring international gold prices are driving up the price of mercury, a toxic metal key in illegal gold mining, to all-time highs. While...