Its always been obvious that DC and US Pacific military commands knew the Japanese would strike at or around 12/7, but everyone thought they would strike US military assets in the Philippines. Striking Hawaii was considered madness (and it was).
I also believe FDR was champing at the bit to have at the Nazis. But there was simply no guarantee an attack by the Japanese on the US anywhere in the Pacific would result in US involvement in Europe. It was not at all certain until Hitler declared war on the US three days after PH.
One point of view well supported is that Churchill knew the Germans and Italy would declare war on the US once the US declared war on Japan. Which was the way it happened.
Let the Japanese surprise attack US forces in Pacific (and should add British owned Hong Kong, Malaya, Singapore were also attacked on this day). FDR took part in this plan- there is little doubt and especially in view of now enshrined democrat machine lexicon and actions the last 80 years, frankly. FDR generally with his State Dept. pals had a hands off attitude (even with the efforts by American Jews to get him to pay attention) toward Germany. This is all in the book cited: “Garden of the Beasts:....... “ in earlier post. It is a great well researched book of what actually happened and what Germany was becoming. Worth the read, as it includes the Stalinist agents work against the US in Berlin well before Pearl Harbor attack, ie during late Weimar Republic.
I think the thinking at the time was the Japanese would strike our South China Battle Fleet under the command of Admiral Thomas Hart. Hart was a veteran of Asia and as such was more than ready when the time came. He was attacked but did not lose a ship and steamed for the Philippines when he could.
He was relieved for health reasons and his outspoken criticism of the actions taken that day and the strategy employed, later vindicated.