I think the strength of the United States' party system---most notably as a two party system---is that it allows for evolutionary change in American society, unlike monarchies, theocracies and the '-isims' governments which periodically end in revolution.

One can argue that Elephants and Asses are really the same political animal, but they aren't; the tension between their core philosophies occasionally goosed by a third party or movement keeps us changing most often for good, one hopes.

The real trick nowadays is finding politicians who are also statesmen. --- John