Germany faced the prospect (even if they didnt expected them to go through it) of a war with France and Britain should they invade Poland.
What would happen if Roosevelt somehow managed to throw the US into the mix and Stalin was persuaded of how a bad idea the M-L pact is (possibly even getting promised gains in Poland for joining)
This means that now for invading Poland Germany faces war with: France, Britain, the US AND the Soviet Union.
Do you think Hitler would still invade or go back? If so what would happen now? As it is clear Germany cant invade anymore without facing an unified front and Germany's economy cant survive without looting?