What to know as President Donald Trump imposes steep new tariffs on imports from Canada, Mexico and China, prompting retaliation and countermeasures.

Business groups, economists and even some Republicans cautioned that new tariffs on goods from Canada, Mexico and China could undercut U.S. industry and the economy.

This will be the golden age of America! Will there be some pain? Yes, maybe (and maybe not!). But we will make America great again, and it will all be worth the price that must be