The problem for Jenkins is that all the voters that know and love him are still registered Dems who will probably be casting dem primary ballots for Manchin. This means the R primary is dominated by the north and panhandle, and likes to select candidates not built for the state at large.
This is what people don't seem to understand about the West Virginia Republican Party. Since WV is overwhelmingly D registered, the Republican nominees end up being very weak because their main base are the WV business class.