How did Roosevelt get the United States involved in World War II without direct military involvement?

Roosevelt dutifully invoked the Neutrality Acts. However, he believed that this was a fundamentally different war from World War I. Germany, he believed (and most Americans agreed with him) was, in this case, a clear aggressor. Roosevelt, therefore, sought to provide assistance for the Allies, while still keeping the United States out of the war. He began by asking Congress to amend the neutrality laws to allow arms sales to the Allies. Later on, after German forces overran France, the president asked Congress for a massive program of direct military aid to Great Britain-an initiative that Roosevelt dubbed "Lend-Lease." In both cases the legislature agreed to FDR's proposals, but only after intense debate