The US had a paradoxical strategy to ensure repayment of its WW1 loans. It would make Germany economically prosperous to ensure Germany was in a position to pay reparations to France and Britain (as per the Treaty of Versailles). This would mean that impoverished Britain and France could keep repaying the interest on their wartime loans to the Americans.
Economist Maynard Keynes, aware that Britain and France would never recover from endless interest repayments, proposed cancelling all war debts. Everyone would end up better off in the long run, as was later proved. But the US government refused and American companies, including Ford, General Motors, and Standard Oil, began to invest in Germany, exploiting its economic collapse and setting the stage for the rise of the Nazis.