President Trump unveiled sweeping tariffs on Wednesday afternoon, announcing a minimum 10 percent tariff on all trading partners as well as so-called reciprocal actions on dozens of other countries, including some of America’s biggest trading partners.

In announcing the new tariffs, his most expansive to date, Mr. Trump said that the global tariffs would help correct decades of unfair relationships and stop other countries from ripping off the United States.

China, for example, will add a new 34 percent tariff on top of a previous blanket import tax imposed on the country’s goods earlier this year. Vietnam’s imports will be taxed at nearly an additional 50 percent.

“If you want your tariff rate to be zero,” Mr. Trump said outside the White House on Wednesday, “then you build your product right here in America.”

Notably absent from Wednesday’s announcement were Mexico and Canada, with whom the United States has long had a free-trade pact. But that does not mean they are immune from the trade actions, a sign of how, combined, all-encompassing Mr. Trump’s policies have become.

Many of the products that come from the two countries have been affected by previously announced tariffs, including those on foreign-made automobiles that go into effect at midnight Eastern time Thursday. Canada, for example, is a huge producer of cars and auto products that are exported to the United States. All finished vehicles from those countries will now be subject to a 25 percent tariff.