I Googled "paint a stop sign post" and the top hit was some town actively seeking people to carry out this near-treasonous act:
"Would you be able to help pick up litter on your walks, organize an Easter egg hunt, paint a stop sign post, change a lightbulb at the clubhouse or maybe plant some flowers? It's your community and you have a right to participate in making us the best that we can be."

Perhaps Graham should notify the National Guard, UN Black Helicopters or a well-regulated local militia and request them to investigate and nullify the threat.