Seems to me that the legitimacy of government is determined by the acceptance of the populace, rather than by legal/historical minutiae, and that the US Government since 1861 is legitimate simply because the vast majority of its people have accepted it as legitimate.

Certainly it's possible that changes in the pattern of governance are needed to retain that legitimacy, which is of course usually the case. What those changes ought to be is of course another story. Unfortunately at the moment most of the impetus toward change seems to be coming from the polar left and right, the places least likely to produce any viable proposal for change. The American people are for the most part not getting behind either program, not because they are ignorant sheep but because they perceive, quite correctly, that the political poles have no productive ideas and many destructive ones.

Unfortunately, the center isn't producing much of value either, and that needs to change. Good solutions develop through competition and cooperation in the marketplace of ideas, and that only happens when people listen to the moderate ideas on the other side and consider them. The shouting around the fringes is unproductive noise.

IMO, as always...