Which christian denomination is represented among america's elite, especially among the ranks of u. s. presidents, all out of proportion to its share of the u. s. population?

It is "The Episcopal Church".

The Episcopal Church is the US-based church of the Anglican Fellowship. A characteristic of importance is the fact that more than a quarter of all leaders of the United States have been Episcopalians. St. John's Episcopal Church, an Episcopal church in Washington, D.C., has been gone to by each sitting president since James Madison.

imperial crisis leads to civil war.

roman forces withdraw from britain as goths attack rome.

odoacer topples romulus augustus

huns attack the empire and drive german peoples ahead of them.