CARACAS, Venezuela — For Vanessa Farina, hope had become dangerous. For more than a year, she had measured out her life by the number of days her husband, the human rights activist and politician Luis Tarbay, spent in Venezuela’s most notorious prison.

Now, with President Nicolás Maduro in U.S. custody and the Trump administration applying pressure, his vice president and confidante, Delcy Rodríguez, had begun to release some of the hundreds of political prisoners it held. Morning and night, Vanessa checked her phone, hoping for good news.