Was the Philadelphia Convention of 1787 a constitutional coup?
No. Although it is possible to argue that the convention exceeded its mandate by producing a completely new structure of government rather than merely “revising” the Articles of Confederation, everybody understood that the Articles had serious structural problems which could net be solved and thus expected something more than a mere revision. Beyond that, the convention had no power whatsoever to force the new sustem on to several states. It was circulated among them and they could accept it or reject as they chose. Had nine states failed to ratify then the constitution never would have gone into effect and some other solution to the country’s problems would have had to have been found. The constitution was adopted with the full consent of the several states after many months of open and reasoned debate among the people.