Sheriff Cyrus Buelton is the main villain in the film Tank. He is played by G.D. Spradlin.
Buelton is the sheriff of Clements County, a large county in northern Georgia. He is extremely sadistic and corrupt, ruling the county seat, a small town near a US Army base, like his own private fiefdom. Along with his small army of corrupt deputies, he controls prostitution and racketeering. Whenever the soldiers from the base visit the town and drink in bars and clubs, eat at restaurants, or sleep with prostitutes, Buelton gets a very large cut. Despite the fact that Army personnel are some of his town's largest clientele, Buelton has nothing but contempt for the armed forces. Whenever he personally deals with a soldier, or even an officer, on or off the base, he is openly disrespectful (and racist if the soldier happens to be black). In addition, he runs a work farm in the wilderness, where he has prisoners beaten and worked nearly to death. This is all done with the knowledge and cooperation of his brother-in-law, a judge.
One night, one of Buelton's deputies, Euclid Baker, gets into a drunken fistfight with soon to retire Master Sergeant Zack Carey. Carey had been chatting with a prostitute on Buelton's payroll, and took an extreme dislike to the way Baker treated her, openly slapping her publicly, so he punched Baker, stole his gun and threw it into a fish tank. Buelton took this as a personal insult, explaining that his officers personal represented him, and to attack them is to attack him. He attempted to have Carey arrested, only to be told by Carey's superior that due to a Supreme Court ruling, US armed forces personnel couldn't be turned over to civilian law enforcement; Carey's punishment for the assaulting Deputy Baker would be handled within the military courts.
Enraged, Buelton dug up everything he could on Carey, discovering he'd recently purchased a boat and had spent years restoring a World War II Sherman tank to perfect running condition. Deciding that the Master Sergeant had money to burn, he attempted to extort him by planting marijuana in his son William's locker at school. He threatened to send the teenager to his work farm if Carey brought in a lawyer, and demanded he sell his boat and pay him over a thousand dollars. If anything went wrong, Buelton swore William would be "shot while trying to escape." Carey, who'd already lost his older son Johnny in an accident years before, was desperate to save William, so he sold the boat and paid Buelton the money. But after he did he warned him that if anything happened to his son, he'd kill Buelton; he said he'd throw away his Army career, his pension, his freedom to get revenge on the evil Sheriff if he went back on his word.
Unfortunately, Mrs. Carey, unaware of how corrupt Sheriff Buelton really was, called in a lawyer, and Buelton, mistaking this as a breach of their deal, promptly had William transferred from the county lockup to the work farm. He told Carey that he'd have to pay him a thousand dollars every year of the boy's three year sentence in order to keep his son alive. He even locked up the lawyer Mrs. Carey had hired. Having had all he could stand, Carey decided to make good on his word - he resigned from the Army, took his restored Sherman tank, and drove to the county jail while Buelton was in Atlanta meeting with the governor. He first humiliated Deputy Baker by ordering him to strip naked in public, then, after freeing the lawyer and other prisoners from the cells, used the tank to bulldoze the building to the ground.
He next drove to the work farm where he freed William, and then the two of them, along with the prostitute, took the tank to the Tennessee border, intending to turn themselves over to the state police there, so that Buelton's corruption could be exposed in a trial. Carey knew he wouldn't get a fair trial in Georgia and neither would his son. An enraged Buelton gathered all of his deputies and made numerous attempts to stop them from reaching the state line. His true evilness was shown when he attempted to "deal" with a man named Gant who gave Carey gas for his Sherman; Gant's brother-in-law had been sent to Buelton's work farm on trumped up charges years ago and died there, and so he was all too happy to assist Carey and his son's flight from the Sheriff. Buelton, deciding to make an example of Gant, attempted to burn his house down, but fortunately Carey doubled back in the tank and drove the torch-bearing mob of deputies away, saving Gant.
Eventually the Sherman reached the state line. Buelton initially blocked the road with trucks, forcing William, who was driving, to go offroad, whereupon Avery, one of Buelton's men, shot the Sherman's engine with a bazooka, disabling it mere feet from the state line. Buelton then demanded they get out and surrender themselves, as he was booed by a crowd on the other side of the Tennessee border, which included the governor. However, a brave biker rode over with a cable, which he and William attached to the front of the tank. People on the Tennessee side used a bulldozer to pull it across. Furious, Buelton ordered his men to fire into the crowd, but was told by the Tennessee state police that they'd return fire if they did, so Buelton instead settled for a last ditch attempt to take the tank by force. He and his men got atop it and attempted to force the hatches, desperate because they knew their authority would end the second the Sherman was across the border, with Buelton screaming that he'd burn them out with gasoline if he had to.
William rotated the turret and used the gun to knock Buelton off of the tank, thoroughly humiliating him. The dozer successfully pulled the Sherman into Tennessee, and Buelton's men, defeated, climbed off, with everyone cheering as Buelton was left sitting in the mud, mutely enraged. Presumably he was later fired for corruption charges and use of excessive force.