Who is Senator Arthur Clay Jellison from Lucifer's Hammer and what is their importance?

Jellison is a fan of the space program, and it's at his request that the United States puts astronauts up to study the comet. Jellison listens carefully to the scientists who talk about the comet and takes the public stand that there's nothing to worry about and no need to panic. Privately, he tells some of his people to buy up camping gear and supplies, just in case the comet doesn't miss after all. Jellison owns a ranch in the mountains above the San Joaquin Valley, and it's there his neighbors gather to create a region that would come to be known as the stronghold. Jellison becomes judge and jury here, ordering the executions or expulsions of those who don't obey the laws as they exist there, including that against hoarding goods that might be used for the common good of the people.