How did the United States prepare for World War II?

Even though
the United States did not enteruntil the attack on Pearl Harbor in December of 1941, it had been
preparing for the likely possibility of joining the conflict for some time. Naval forces around
the Pacific had been actively operating drills and exercises to stay sharp and prepare as
tensions with Japan increased. As the Japanese Empire expanded closer to the Philippines,
President Franklin Roosevelt issued a national emergency declaration that gave him significant
authority to oversee military and civilian coordination.

As late as 1940,
Roosevelt had been corresponding frequently with British Prime Minister Winston Churchill about
contingencies should the United States join the conflict. Although he assured the nation that he
planned to keep the United States neutral, privately he wanted to join the fight against
fascism. The two leaders frequently discussed how the countries would assist each other in the
war. In fact, diplomatic missions between the United States and Great Britain, the Soviet Union,
and China increased significantly during this time.

Roosevelt also bolstered
the Office of Naval Intelligence in its efforts to gather information through clandestine
operations around the globe. US intelligence officers were stationed in many countries involved
in the war to gather as much useful information as possible.

Aware that the
United States might become a target as a result of its support of Allied forces, coastal
defenses were built up around major American ports. The country also instituted a draft in 1940
to shore up its defense forces: the only peacetime draft in the country's history. The pre-war
period was also marked by increased military recruiting.

Furthermore, the
manufacturing of supplies and equipment vital to the war effort was ramped up, particularly the
production of munitions, tanks, military trucks, and warplanes. In fact, after the fall of
France in 1940, Roosevelt asked Congress for one billion dollars to be used in warplane
manufacturing.

Roosevelt also reconvened the National Defense Advisory
Commission (NDAC). This body of industry leaders and public consumers was first created during
World War I. It served to advise the government and act alongside it to implement private sector
efforts to prepare for war. In January of 1941, the president replaced the relatively toothless
NDAC with the Office of Production Management (OPM). This body was charged with encouraging
industrial production to aid a potential war effort.