In the tumultuous final weeks of Donald J. Trump’s presidency, he signed into law, with little fanfare, bipartisan legislation that gave the United States vast new powers to police doping at competitions like the Olympics.
The law authorized the Justice Department to criminally prosecute coaches, trainers, doctors and sports officials from around the world involved in facilitating doping, even if the event was held outside the United States.
Nearly four years later, simmering anger among global athletic authorities about use of the law has exploded into public conflict. That has left the Olympic and antidoping movements unsettled as the Summer Games prepare to open on Friday in Paris and raised new questions about the reach of U.