Excuse me. The French and British did not get off their bellybutton fast enough to stop them? Thank god for the US ploughing in so quickly then and saving the world just a mere four and a half years later, with their timely arrival in France.
I should have explain my self on that remark. The allies (French, U.K, Blegium, Holland) should have attacked Germany when they declare war on them. They had six months to do this but instead sat there and did nothing. If they have invade, it would have hurt Germany. Germany did not have a panzer division, 2 division (may be wrong on that) that guard the west while the rest where playing in Poland.
Reason why U.S. did not want to jump in the war (1940) was political reasons and they really did not have a military to support the allies. By the time they enter the war, it was decided (Politically) not to invade France in 1942 for good reasons: 1) Green U.S. was not ready to pursue a invasion into a heavy occupied France and they where busy in the Pacific, 2) U.K had their hands full in North Africa and Pacific, 3) If the allies did invade France (1942-1943) they would most likely be slaughter by the Luftwaffe that dominated the sky's over France.