The president of the United States is elected to up to two terms of four years each by an electorial college assigned based on the popular vote of the American citizens. It's clearly laid out in Article II of the U.S. Constitution. With the buzz around Gordon Brown rising to Prime Minister before the end of the current parliament, I got to wondering how does the Prime Minister get elected? From what or whom is his power derived? Is he or she essentially the equivalent of the House or Senate Majority Leader. What research I have done outlines a complex system of custom and folklore intermingled with an opaque role of the British Sovereign (presumably Elizabeth II?). Is there anybody out there from the UK willing (or able!) to explain it to me?