President Trump’s broad tariff rollout takes aim at the U.S. trade deficit, which he calls a “national emergency.” Here’s how the trade deficit works, how tariffs affect it—and why economists say it isn't necessarily bad for the economy.

Outwardly at least, President Donald Trump continues to take a hard-line stance on China with tariffs of 145 percent and higher, even after easing off earlier trade offensives against other partners. China, which has vowed to "fight to the end," has responded with its own steep tariff hike and a range of other countermeasures.