mudhen,
Definitely fight this. A quick search of "right of eminent domain" on wikipedia showed that the Supreme Court has always upheld each state's right to define the use of eminent domain. So, it will depend on how WV defines the right to use eminent domain.
I then searched for WV right of eminent domain and found this link:
http://www.legis.state.wv.us/WVCODE/code.cfm?chap=54
This paragraph stands out to me:
"§54-1-1. Bodies which may exercise power of eminent domain.
The United States of America, the state of West Virginia, and every corporate body politic heretofore or hereafter created by the constitution or statutes of the state, and every corporation heretofore or hereafter organized under the laws of, or authorized to transact business in, the state, for any purpose of internal improvement for which private property may be taken or damaged for public use as authorized in section two of this article, shall have the right of eminent domain, and may exercise the same to the extent and in the manner provided in this chapter, and subject to the restrictions and limitations provided by law.
Specifically the part in bold. I don't understand legalese that well but could "internal improvement" mean only if the improvement is internal to the state of West Virginia? Hopefully someone else will be able to help with this.
Also focus on the definition of public. Since the supreme court recognizes the right of the state to define eminent domain, would it be for the benefit of the state's public, not that of another state?
Since this is a legislative issue, be sure to write to every incumbent on your ballot and let them know that if you don't see immediate support on this they will not receive your vote. Get them to take a stance. Even if they aren't up for reelection, it will take a couple years to build a line like this so you can go after those representatives that are up for re-election in a couple years. Let them know that they will lose your entire county's votes if they don't eliminate this threat.
Best of luck!!!!