More than a decade after the Sept. 11, 2001, terrorist attacks, the tragedy haunts Washington policymakers who are deadlocked over how to protect the country against cyberattacks. Current and former government officials have spent months pointing to 9/11 as a harbinger of what could occur if Congress, federal agencies, and businesses don’t act to update policies that govern how cyberthreat information is shared; how threats are monitored; and what standards should guide national cybersecurity.