But the nation is not at war.
A small volunteer military force is at war.
The ADMINISTRATION, for heaven's sake, is not even at war, except possibly the Defense Department. Possibly.
The reason your faux Dewey speech would have been inconceiveable is because the Roosevelt administration understood the meaning of war, and because they, through executive orders and enabling legislation transformed the nation into a warmaking machine in just a few short weeks between December 8, 1941 and mid-February, 1942.
They understood that press censorship, full-time propaganda operations, total control of labor and capital, unlimited expansion of the armed forces, internment or expulsion of enemy aliens, militant border control, and rapid, even reckless, military operations directed at conquest and subjection of the enemy were all required to mobilize that nation for war, and to keep it there.
This didn't hurt, either:
..."the President is hereby authorized and directed to employ the entire naval and military forces of the United States and the resources of the Government to carry on war against the Imperial Government of Japan; and, to bring the conflict to a successful termination, all of the resources of the country are hereby pledged by the Congress of the United States."
George Bush could have had anything he asked for on September 16, 2001. He didn't ask for much.
Horse droppings.