This should never be a problem in a campaign, and it is best dealt with early in the candidate selection process by making sure ALL possible candidates are probably acceptable to the largest party coalition members.
It's that simple!
We did this with Goldwater, and although the Rockefeller Republicans are blamed for dropping the ball in the Eastern states, his bigger problem was with the very segments of the party that wanted him to run ~ mostly in the Midwest.
Best bet at this state is to fire ALL his campaign staff and advisors and bring in a boatload of Conservatives.
Who would be considered the largest party coalition members? The so called base if you will, of republicans? I don’t mean the base of over 30 years ago, but the base now in 2012?