In 2019, ransomware had yet to emerge as one of the top national security concerns confronting the United States, an issue that would become the focus of a presidential summit between Washington and Moscow this year. But the attacks in Texas were a harbinger of the now-exploding threat and offer a vivid case study in what happens behind the scenes when small-town America comes under attack. Texas communities struggled for days with disruptions to core government services as workers in small cities and towns endured a cascade of frustrations brought on by the sophisticated cyberattack, according to thousands of pages of documents reviewed by The Associated Press and interviews with people involved in the response. The AP also learned new details about the attack’s scope and victims, including an Air Force base where access to a law enforcement database was interrupted, and a city forced to operate its water-supply system manually.