The last time I called him on it, he explained that he was simply arguing a counterfactual...but he keeps coming back to it and picks July 4th for this marvelous sentiment:

Ultimately, I think the United States is a pretty awesome country but it very plausibly would have been even awesomer had English and American political leaders in the late 18th century been farsighted enough to find compromises that would have held the empire together.

Way to be patriotic, Matthew!!