Trump's tariffs on Canada, Mexico and China suggest he is willing to risk a global trade war. The main thing that could stop him would be a stock market selloff.

Here’s how current events are mirroring a key point in U.S. history that led to a trade war and exacerbated the Great Depression, according to economists.

President Donald Trump’s ambitions for a reordering of world commerce are broader. The opposition — at home and abroad — is weaker. And the economic risks he seems prepared to run may be greater.