The World's Greatest Sinner (1962)

As a sinner, he’s a winner!

A bored insurance salesman quits his job to go into politics. He first starts preaching about how man is greater than he thinks and that man can live forever. He ends up forming his own political party, "The Eternal Man" party. He begins to be referred to as "God". Then he starts having doubts about the eternalness of man.