Congress shares its bicameral (two-house) structure with many legislatures throughout the world, but it differs from most legislatures in other important respects. Most legislatures around the world follow the so-called Westminster model, named for the United Kingdom's Parliament. In the United Kingdom and other Westminster-style systems, legislatures elect the country's chief executive, usually called the prime minister, from the ranks of the majority party in the parliament. The prime minister then selects cabinet ministers, mainly from among members of parliament, so the parliamentary majority also runs the executive agencies. The U.S. Constitution, in contrast, specifies that Congress and the president be elected separately, and that members of Congress cannot serve in the executive or judiciary while in office. The separation of Congress and the executive means that presidents are never assured that their legislative proposals will be accepted. Indeed, many presidential initiatives are declared “dead on arrival” when they reach Capitol Hill—that is, they are unlikely to be approved by Congress....
