President Trump's tariffs took effect earlier this morning, hitting nearly all U.S. allies with punishing new levies and raising import taxes on Chinese goods to more than 100 percent. China has already responded with its own levies, and the E.U. is preparing its own retaliatory tariffs on American products starting next week. These plans, and others like them, have heightened fears of an economically damaging trade war and a global recession, as losses mount in stock markets around the world.