Could the Nazis ever have successfully invaded the USA?
Ok lets say Pearl Harbour never happened or at least was delayed for at least a year and lets say the US decided to be strictly neutral during the war could they have been successfully invaded had things took it course?
Now had the USA left Britain to its fate though they would've fought on valiantly BUT as a island nation they would've eventually had to have given in or at the least sued for peace this would've left Nazi Germany incharge of the whole of Europe. Now with the western front gone they would've spent all there resources invading the USSR and they could've succeeded cause nearly the whole of Europes resources which the Nazis had under there control would've been used plus they wouldn't have needed to send tanks to North Africa to fight the British and i believe the Nazis would've beaten the soviets which would've meant the Nazis would've controlled the resources of not just Europe but Russia and its territories. With Britain impotent nothing wouldve stopped them from taking the British empire which would've meant the Middle East and India could've fell under Nazi control.
Now after that the Japanese then wouldve gone on the warpath and taken the whole of south east asia including Australia cause there would've been no Royal Navy to protect Australia. So now you got Nazi Germany and Japan Practically controlling nearly 2 thirds of the global resources and population.
Now you got South America which alot of countries certainly had pro Nazi sympathy's plus if the Nazis or the Japanese could capture the Panama Canal that would've split the US navy in two reducing its effectiveness.
So now you got a situation where the whole of Europe, Asia, Middle East and prolly South America is under Axis control just leaving the USA and Canada free countries and could they resist a massive invasion from both its coasts plus nearly all of the USA major cities are located near coastlines ripe for seaborne invasion.