We had partially cracked JN-25 but our understanding was still verrrry incomplete.
I share your beliefs regarding likely Brit action/non-action re: US/Pac.
The Brits were absolutely desperate and came within just maybe HOURS of losing the Battle of Britain.
If they hadnt enraged Hitler away from destoying the RAF via tempting him into The Blitz, well, today we might not much later have ended up seeing the UK and all of Europe taken over by fatalistic modernity-haters.
By winning, The West lost.
Had Winnie known ahead of time, well, he probably didn’t let on to us, I think.
“What if” is always difficult, but if the Japanese had not attacked Pearl Harbor there could have been nothing but minor skirmishes in the Pacific between the US and Japan for months if not years—the US would have stayed out of the war during that period (due to popular opinion against the “foreign war”) and the British would have been doomed.
“Who benefits” is always a good starting point for unraveling mysteries.
We probably would have been dragged into the war eventually—but we did not get to choose the time and place.