Prelude or not, it was a strategic mistake to poke a sleeping giant in the eye.
Without attacking and neutralizing the US bases in PH, pray tell me how Japan could have attacked US bases in the Philippines only 8 hours after PH and expel the Americans.
This is how its main source of oil in Indonesia came under its grips. It invaded Indonesia and expelled also the Dutch colonialists from there.
So, attacks on the PH bases opened many other opportunities for the Japanese military in the SE Asia. It expelled France from Vietnam, Laos and Cambodia. It also expelled the British from Malay, Singapore and Burma.
It was Japan all alone fighting the USA, British, Holland, France and British in the Asian front. More to that, it was also fighting a heavy war against China.
So, it is easy to say that attack on PH had woken up the US population. Many things depend upon the situation. The same could have happened without even a PH attack, such as the US troops expelled by the Japanese from the Philippines.
So, we cannot just say for sure that USA would have remained un-involved in that war if there was no PH attack by the Japanese.