Washington has the right to block US federal agencies from buying products by Huawei on cybersecurity grounds, a judge has ruled, dismissing the Chinese telecom giant's legal challenge to a purchase ban. Huawei filed the suit nearly a year ago, claiming that Congress had failed to provide evidence to support a law that stopped government agencies from buying its equipment, services, or working with third parties that are Huawei customers. The dispute was one of several fronts in a bruising trade war between Beijing and Washington, which has accused the tech firm of stealing trade secrets from American companies and warned allies that its equipment could be used to spy on other countries.