Trade was slowing, but still growing.
Trade declined and collapsed in the few years after Smoot.
Further the idea of world trade, free trade, commerce across national lines, that idea was flushed, by Smoot, and Hawley, down the drain, especially in Germany and Japan.
And, guess who filled the void with hyper nationalistic jingo?
I could argue that 60 million dead and the economic waste of the thirties, the destruction and war of the 40’s the comparative strength of the Soviet Union and Communism could be laid at the foot of those two idiots.
Was it Smoot Hawley, or Reparations for WW1?
Japan had chosen the British Model, they saw the Greater East Asia CoProsperity Sphere as a tool for expansion and economic dominance, they wanted to be the British Empire of the 18th Century in the 19th Century.
And I would say that is a false argument, Smoot Hawley effected imports, not exports, what kicked off WW2 in the Pacific was embargos on shipping oil and steel to Japan, it had nothing whatever to do with Smoot.
Additionally, the decrease in trade could just as easily be attributed to the general Recession that rebounded around the world.
Smoot has become something of a shiboleth, and wars have not stopped being fought, far from it, if anything wars in the future will be far more bloody, how close did India and Pakistan come to a nuclear exchange in the 90’s?