Upon further review - Smoot-Hawley was passed in June 1930, hardly before the market crash.
Both Doug Irwin and Mario Crucini, in separate studies, have shown that when you factor in DEflation, HS probably "hit" this country for 5% of GNP!!! This is an incredible shock, and doesn't factor in the "trade wars" and reciprocity barriers that were effected afterwards. I suspect the actual "death toll" for HS is probably higher.
Want to put that in perspective? Most economic historians find that the railroads only ADDED about 5-10% to the GNP in the entire 19th century. So in a couple of years, Hawley Smoot wiped out everything it took the railroads 80 years to add!!!