The Ancient Greeks are often credited with being the founders of the modern democratic society, but this is of course debatable. The Greeks, consciously or not, had their own influences from the past. The thing about history is that we are constantly discovering new things, debating existing evidences or interpretations, et cetera. This occurs so much that the exercise of assigning a 'beginning' to a concept so vague as "political and military lineage" becomes pointless and arbitrary. Nothing really truly begins, in the sense that there is always something - however insignificant - that happened beforehand. There are simply too many variables to consider. Even within your own theory of lineage there are so many vital influences which have been left out (concerning the formation of the modern United States of America) - Renaissance Italy and Revolutionary France being two of the most critical which I can think of off the top of my head.

And so we come to the problem that for the purposes of your question, an arbitrary point of origin must be chosen for the sake of facilitating discussion and answering your question. I believe the appropriate origin would be Ancient Greece, but such a broad generalization requires an equally broad and heavily opinionated answer, and as such, my answer is as good (or bad) as any.