In World War II, was there no mixing of U.S. and British forces and commands?
As to the state of rapport between the British and American commands in WWII, I would refer you to the movie "Patton". I am assured by several senior members of our local American Legion Post that the portrayal in this movie is entirely accurate. The supreme Allied Commander was an American (Eisenhower) and the Supreme NATO Commander since the war has always been an American General.
This does not mean that there was no cooperation in specific cases, or out of immediate necessity, but the ultimate authority has always been the American Chain of Command. (At least until Bubba got hold of it!)
You are bringing up a rational point in this thread? Fool!
Seriesly, of course there was mixing. After Ike left Italy in 1943, General Maitland Wilson was appointed Supreme Commander of the Mediterranean Theatre. General Alexander commanded the 15th Army Group under him, which consisted of the 5th US Army and the 8th BritishArmy.
FDR actually wanted Marshall to command all of the Western Fronts, but Churchill vetoed that. FDR then decided Ike would command Overlord instead of Marshall.
get a copy of CROSSBORDER WARRIOR & read it. you'll see how Canada, GB & the USA "went out of their way" to assure that foreign nationals serving with allied units did NOT have to swear allegiance to any foreign power.