I would say America as such is not to blame, but the global economic system at the time, coupled to the circulation of debt.
Debt circulation: After the Versailles treaty Germany was bound to pay reparations to the victors (France and Great Britain mainly). America loaned money to Germany, which they in turn used to pay the repairs, which France and Great Britain in turn used to pay their debts to America.
In addition the economies of the European countries lay in shambles post WWI. The US benefited from this initially, through the global food shortage, by increasing wheat production. After a while the European agriculture recovered and prices dropped dramatically, and farmers whom had loaned large sums to grow their business went under causing banks to collapse, next to other forms of 'bad' credit that was readily given out by these banks. In short this collapsed the US economy, the largest in the world. Loans were called in, dragging the European countries down with the US.
Some say that had the victors been more realistic in their terms with regards to Germany, and possibly accepted pay in kind allowing Germany's economy to develop in stead of deliberately frustrating it, the crisis would not have been so deep, due to the lack of the debt circulation described above.
Others argue that the US, as the new leading global economy, didn't take enough responsibility with regards to giving out credit in their domestic economy to ensure economic stability.
I personally feel the crisis is the result of a combination of both, as supported by the way the US and allies dealt with the aftermath of WWII.
Sources:
I'll ad the exact chapters later