If I reflect on Darwin evolutions of thinking can see how American community only survive through constant socio-cultural change. Federative coutry need constitutional community to form it and if we see how leader perception today influece on policies .There is so much struggle internally reflecting deep sociological issues. Its not just opposing different parties Im speaking beyong any ideological belief, there is a deeply divided nations, strugle between ethnic group . A sense what has served there to justified norms that follow by the constitutions So is it possible that America is going through dissolution, there are ways to look at it in my opinio.
If you compare the position of the Union in 1789, and compare that with what the US President and Congress does at present, it is difficult to think that it is the same Constitution in position. In fact, it is from the Great Depression onwards that the federal government stared expanding, to where today, even on issues where it should be the County/ City/ State who should be taking the lead, it is DC which is held accountable. If there is one word/ phrase to describe why, it is 'change' and the reaction to it. Whether it was the democratization of politics, the social churn cause by urbanisation, creation of large economic players which pushed an aggressive foreign policy ('talk softly and carry a big stick'), the (unwilling) involvement in WW I and much more willing in WW II, the big Keynesian push in the 1930s - all these and more led to the enlargement of government responsibilities and creation of specialized agencies. The Cold war and the imperative of using economics and military as the metrics to measure power and dominance could only come from greater centralisation. It is amazing that those who wanted a smaller government left larger deficits.
This combination of internal and external challenges and opportunities, and the US leadership reacted to them, formed (or did not form) consensus of how to deal with them, and the inherent logic of large forces, once created, moving on and gathering momentum till entropy stops them, best explains the changes.