I'm not an expert on this but I'm speculating "fracking"
Which uses high water pressure to extract the coal.
15th Amendment: "The right of citizens of the United States to vote shall not be denied or abridged by the United States or by any State on account of race, color, or previous condition of servitude."
This should give you the idea I hope this helps :)
Using the map, the central meridian of United Arab of Emirates is found in the State of Sharjah, UAE. That's 50 degrees, 45' 41" East. That same central meridian also passes in the states of Idaho, Maine, Minnesota and Arizona.
Answer:
centralized control of the empire faded