[Legbreaker]

I think this is rather telling. http://www.g2mil.com/thompson.htm

In the first six months of 1942, there was “an aggregate of 397 ships sunk in U.S. Navy-protected waters. And the totals do not include the many ships damaged. Overall, the numbers represent one of the greatest maritime disasters in history and the American nation’s worst-ever defeat at sea.” In return, the US Navy was only able to sink six U-boats! (During the same period, the British et al. were credited with 32 U-boat kills.) So dire was the situation that at one point General George C. Marshall, US Army, wrote to Admiral King to say “‘another month or so of this’ would so cripple their means of transport they would be unable to bring US forces to bear against the enemy.” Indeed, the Germans had a very good chance of disabling the entire US east coast, as Hickam told us, if only Hitler had permitted Doenitz to have the required numbers of U-boats, and the time to do it. If that had happened, Hickam speculated that the losses to the US “might have proven terminal.” During those deadly months of 1942, “The American Atlantic coast no longer belonged to the Americans. It quite literally had become the safe hunting ground for the U-boats of Nazi Germany,” said Hickam, with U-boats destroying US ships “just a few miles off Norfolk, practically within sight of the American fleet.” Admiral Doenitz told a reporter in 1942 “Our submarines are operating close inshore along the coast of the United States of America, so that bathers and sometimes entire coastal cities are witnesses to that drama of war, whose visual climaxes are constituted by the red glorioles of blazing tankers.” By the end of June, Captain Wilder D. Baker, US Navy, finally said something about his Navy’s poor showing in the Atlantic – “‘The Battle of the Atlantic is being lost.’”

Reading that it would seem quite possible for the US to have been knocked out of the war, at least in Europe, leaving the Commonwealth to go it alone.

A few paragraphs earlier it mentioned the Japanese never really bothered sending their subs to attack US shipping in the Pacific (even though the Germans constantly urged them to) and if they'd done so right from the beginning (December 1941), the US would have been extremely hard pressed to achieve anything there as well.

As I read more and more of this, which was written by an American using primarily American sources, the more it shows the US did not contribute as much to the survival of the Commonwealth as it claimed. I find one particular paragraph of great interest:

It is also ironic to note that the US Navy also apprompted or bought warships from Canada and the UK (including an aircraft carrier, HMS Victorious). This last comment is a minor, perhaps trivial point of course, but it, along with the U-boat hunting statistics mentioned above and the reality that Canadian and British ships had to escort allied shipping through American waters, surprises many who espouse the traditional “If it weren’t for us, you’d all be speaking German” polemics so often recited in certain lay circles. Actually, when the British deployed some two dozen ASW trawlers to the US east coast in 1942, the British viewed it as a “rescue mission.”