“Isn’t this how the Depression started?”
No.
Not even close.
It began after the stock market crash of October 1929, which sent Wall Street into a panic and wiped out millions of investors. Over the next several years, consumer spending and investment dropped, causing steep declines in industrial output and employment as failing companies laid off workers. By 1933, when the Great Depression reached its lowest point, some 15 million Americans were unemployed and nearly half the country’s banks had failed.
Smoot-Hawley Tariff Act: The consensus view among economists and economic historians is that the passage of the Smoot-Hawley Tariff exacerbated the Great Depression.
Part and parcel.