Big changes are underway in the United States, as the country gears up to elect a president, one-third of the Senate, and the entire House of Representatives this November. The outcome will have profound consequences for U.S. economic policy, and thus for the global economy.

As it stands, Hillary Clinton remains the front-runner for the Democratic nomination, ahead of her socialist opponent, Sen. Bernie Sanders. The bombastic billionaire Donald Trump is leading the Republican field, followed by firebrand Sen. Ted Cruz of Texas, Sen. Marco Rubio, a talented mainstream conservative from Florida, and, further back, popular Ohio Gov. John Kasich.

It is impossible to know whether these trends will hold through the rest of the primaries. America's media is consumed by the various possibilities. Can Rubio rally a broad coalition, or will Trump win the Republican nomination? Would a Trump nomination help Clinton win the general election?