Itis actually a classic and genuine "WHAT IF..." scenario:
in May 1942 it could have gone the other way as Arnold was advocating "packing up the dishes and go home" strategy. That is a quote from him and I am busy finding the source for that one.
King was focused on the Pacific, fair enough, insofar as the USN was the main force there.
Marshall was all for a "Germany first" strategy, but was having an uphill battle as the feeling was that the British were sliding and not sticking to commitments.
Of course it did not exactly help that the British had a very professional planning and management team. And they must have let the US generals know that they were regarded as very green in modern war.
US enthusiasm not matched by reality also put strain on it all.
So, May 1942: Britain is not interested in committing suicide on invading France.
FDR is being convinced that either US troops gets to grips with Germany or it is off to the Pacific.
I am not sure the US factories produced for warehousing if Britain could not use the output. As far as I know, the rapid expansion of US army and USAAF would have taken care of any spare capacity.
Could Germany have done anything to keep the focus on Europe? the "happy times v2" along the US East Coast was bad news, but how much did it do to public US opinion vs. PH?
FDR was a politician and I believe that if the public opinion was squarely behind a "Japan first" strategy, he would have backed that. BUT that is speculation.
Reading Fenby's "Alliance", the special relationship was more Churchill clinging to the US than a 2-way street.
So, without US intervention (even counting for the slow ramping-up) was Torch going to happen if it were Britain only? doubtful
Cross-channel in 1944? if Japan had been defeated, well maybe. But I cannot see Britain doing it alone.
If Britain is withdrawing its shipping from US usage? I am not clued up on the amount of shipping in 1942 or 1943 going to what destination and under which flag.
So, IF US is leaving Britain to do its own fighting?
Ivan