Let's see. The Allies had massive superiority in the air and in the sea. A better german reaction, even a free hand for Rommel, could have meant more (much more) allied casualties, but not a failure.
The only way I see a possible failure has to be through intelligence. If the germans somehow knew the place and time of the invasion and were able to keep this knowledge in secret, they had a chance. Of course, they would have to concentrate armor, planes, V-1's, and their best troops on the beaches, and assume big losses themselves, but they could have done it.
In this event, the allies could very well have postponed Dragoon (Churchill was always against it) and try to push elsewhere (Italy, Balcans). The worst side of it would have been the total loss of the airborne divisions, hig-trained specialists, essential to a new attack.
The only way I see a possible failure has to be through intelligence. If the germans somehow knew the place and time of the invasion and were able to keep this knowledge in secret, they had a chance. Of course, they would have to concentrate armor, planes, V-1's, and their best troops on the beaches, and assume big losses themselves, but they could have done it.
In this event, the allies could very well have postponed Dragoon (Churchill was always against it) and try to push elsewhere (Italy, Balcans). The worst side of it would have been the total loss of the airborne divisions, hig-trained specialists, essential to a new attack.