 Lone actors are notoriously hard to detect and hard to prevent from engaging in violent activity. They typically don't talk to other people, so it is harder to detect an individual who isn't in communication with others. A former Marine vet and volunteer firefighter was killed at the rally. Two who were wounded are in stable condition. President Biden addressed the assassination attempt during a brief speech from the Oval Office last night. The power to change America should always rest in the hands of the people.