This business about Smoot-Hawley is pulled out every time this subject comes up. What the people who point at Smoot-Hawley with quavering fingers conveniently ignore is that there were two tariffs acts a decade before Smoot-Hawley that raised tariffs much more.

There was the Emergency Tariff Act of 1921, and the Fordney-McCumber Tariff Act of 1922. Back-to-back tariffs increases, and dramatic increases too.  What happened after these tariff acts?

We got the Roaring Twenties.

Smoot-Hawley was a pimple on the butt of a pissed off bear, and the bear was the collapsing banking/financial system of the world, not just the US.

Back then, when banks failed, there was no depositor insurance. If you had money in the banks that failed, you lost your entire deposit amount. The result when this started was that there were "runs" on banks - people would mob the other banks associated with a failed bank, and they'd line up and demand their money out of the bank. At some point, the bank's reserves would be expended, and the bank would fail just from the run. The result was that people pulled their money out of banks and shoved it into coffee cans under the sink, because they didn't trust banks. This situation persisted until FDR declared the "bank holiday" in 1933, where banks closed for three days, and FDR said that "only the sound banks will re-open." Funny thing, nearly all banks re-opened, and then people started re-depositing their money.

The Federal Reserve was supposedly created to backstop banks, but some of the regional Fed banks wanted to defend the value of the US dollar more than they wanted to stabilize the financial system. The Fed is supposed to be "the lender of last resort" and lend to banks that are experiencing high loan failures or runs on the banks at higher rates. This is what is called "discount window" lending. Some of the regional Fed banks did this. Some did not, in particular the St. Louis Fed bank.

Whenever we have a financial panic in this country, your first instinct should be to look at the banking sector. That's where the hucksters usually hide. It was true in 1873, it was true in 1907, in 1930, it was true in 2008.