Not necessarily so, Rapaire. Germany could easily have not declared war on the US---or delayed it substantially---which would have complicated FDR's calculations considerably.   Hitler was not exactly the most honorable negotiator elsewhere.

Nobody, as far as I can tell, is arguing that the US should not have supported the UK etc. Just pointing out the awkward situation FDR was in up to Germany's declaration of war.

It's also interesting that the US Ambassador to the Court of St James 1938 til November 1940, Joseph P Kennedy, was an embarrassment--not only anti-Semitic but defeatist--and FDR sought to dampen his influence. And when the US did enter the war, Kennedy blamed FDR personally for the death of his oldest son in the war.

But it's possible we're edging into rather egregious thread creep.