Coterminous: having the same boundaries or extent in space, time, or meaning.
From New York Magazine, by Jonathan Chait:
“The regular Republican Party of tax cuts for the rich and deregulation of polluters and the financial industry once seemed to be set apart from its clownish demagogue presidential candidate. In rapid order, the strands have merged together into a party disdainful of transparency and united in self-enrichment.”
I Tried Being Tasteful... 