I am not sure that I agree that Manchin will probably win. It depends a lot on the campaign, and how Manchin chooses to position himself.
Two hypothetical questions then:
1) Do you think Manchin is a talented enough of a politician to figure out how to choose to position himself?
2) Do you think Manchin will do that, if necessary, to win?
Based on your quoted bit above, unless you think one in Machin's position can tell himself that the West Virginia climate in November, 2010 will be something other than it appears today, well, I think it speaks volumes.