For the last 44 years, Kelleher has run for office 16 times and lost 15. His only taste of victory came in 1971, when he was elected a delegate to Montana’s Constitutional Convention. There, he helped replace the state’s century-old territorial constitution with one of the most progressive governing documents in the nation. Kelleher’s political passion then, as now, is unique - and largely unpopular: He wants to replace the U.S. Senate, House and presidency with a parliament. Under a parliamentary system, citizens vote for parties, not individual candidates. The party with the most votes selects a prime minister, who...