Nazi Germany was allied with Italy and Japan (the Axis powers). At the time Nazi Germany and the Soviet Union remained allied under the Molotov-Ribbentrop Pact and had jointly invaded Poland in 1939, an alliance that remained until the Nazi invasion of the Soviet Union in 1941.
Roosevelt had called Detroit, Michigan as the "great arsenal of democracy" in reference to the rapid transition of much of the Detroit-area automotive industry's conversion to produce weapons during World War II. The speech was "a call to arm and support" the Allies in Europe and to a lesser extent in Asia, in their struggles against totalitarian regimes.
After establishing the danger, the president then proceeded to request action from the people. He acknowledged a telegram he had received. He refuted its message, which he summarized as "Please, Mr. President, don't frighten us by telling us the facts." The central fact Americans must grasp was, "If Great Britain goes down, the Axis powers will control the continents of Europe, Asia, Africa, Australia, and the high seas—and they will be in a position to bring enormous military and naval resources against this hemisphere."
He then continued to describe the situation in Europe, punctuating his remarks with warnings how the Nazis would use the same tactics in the Western Hemisphere, and giving vivid imagery such as "The fate of these nations [occupied by force by the Nazis] tells us what it means to live at the point of a Nazi gun." Roosevelt attacked the British prewar policy of "appeasement," calling it ineffective. Listing prior examples given by European countries, he said it was futile.
The only solution was to assist Britain ("the spearhead of resistance to world conquest") while it was still possible.
While not explicitly pledging to stay out of the war, he stated that "our national policy is not directed toward war," and argued that helping Britain now would save Americans from having to fight. "You can, therefore, nail–nail any talk about sending armies to Europe as deliberate untruth." Europe does "not ask us to do their fighting. They ask us for the implements of war, the planes, the tanks, the guns, the freighters which will enable them to fight for their liberty and for our security. Emphatically we must get these weapons to them, get them to them in sufficient volume and quickly enough, so that we and our children will be saved the agony and suffering of war which others have had to endure."
He urged this to change, all the while stressing that open war would not hurt the country: "the strength of this nation shall not be diluted by the failure of the Government to protect the economic well-being of its citizens." He focused on that theme of "splendid cooperation between the Government and industry and labor" for several paragraphs, cited how American labor will make an impact in the combat zones, and noted how important the manufacture of weapons and vehicles is to being strong as a nation.
He warned against labor disputes, saying, "The nation expects our defense industries to continue operation without interruption by strikes or lockouts. It expects and insists that management and workers will reconcile their differences by voluntary or legal means."
Roosevelt stressed that it was not the American government but the American people who had the power to turn the tide of the war. It is here that he uses the phrase "arsenal of democracy": "We must be the great arsenal of democracy. For us this is an emergency as serious as war itself. We must apply ourselves to our task with the same resolution, the same sense of urgency, the same spirit of patriotism and sacrifice as we would show were we at war." Finally he reassured the American people: "I believe that the Axis powers are not going to win this war."
Previous policies such as the Neutrality Acts had already begun to be replaced by intensified assistance to the Allies, including the cash and carry policy in 1939 and Destroyers for Bases Agreement in September 1940. The Lend-Lease program began in March 1941 several months after the Arsenal of Democracy address. After the Japanese attack on Pearl Harbor in December 1941—less than a year after the Arsenal of Democracy address—the United States entered the war.