Crib Sheet: David Cameron, Prime Minister of the U.K., My Perfect Cousin

You think choosing a new Pope is a long-winded process? Well, try electing a new Prime Minister in the U.K. Over there, the parliamentary system works on a first-past-the-post basis, meaning that, in order to stick its man in Downing Street, a political party has to win over half of the 650 seats in the House of Commons. No outright majority, no keys to Number 10.

So, six days after the country went to the polls, a puff of white smoke has appeared above the rooftops of the Palace of...