The best way to declare war on a spy as an ordinary person is to become a spy as well. As a spy, if you want to go to war with a powerful espionage organization, join an equally powerful espionage organization. If you are unable to join any powerful espionage organization, then establish your own espionage organization and fight until destruction or victory. This is the war of spies, telling the story of how a group of ordinary people achieved extraordinary success.
For an ordinary person to wage war on a spy, they would first need to become a spy. For a spy to wage war on a powerful spy organization, their only option would be to join a different yet equally powerful spy organization. If they are unable to join a powerful spy organization, then they would need to establish a spy organization that could go to war with one until victory is obtained or until they perish. This is a tale about a group of ordinary people that manage to accomplish extraordinary deeds while participating in the war between spies.