Enlightened self-interest.
This may be one of the crazier objections to evolution. (But then, are there any sane ones?)
Even without evolution, everyone knows that if we trace our ancestors back far enough we find some bad people. Maybe a criminal here and there, perhaps a wanton woman, a slave or two, that sort of thing. Go back further, and our ancestors were all pagans. Further back, they were barbarians, and before that they were savages, perhaps cannibals. We know this is our ancestry, even if evolution were never dreamed of.
But so what? Does anyone, knowing that, decide to be a savage, or a criminal? Or a pagan? The morality, or lack thereof, of our distant ancestors is meaningless regarding the kind of people we choose to be. So what difference could it make if, hundreds of millions of years ago, our ancestors weren't even human?
You have it so stuck in your head that Evolution is some kind of satanic plot, and no one who believes in Evolution could possibly be a good Christian, that you're just way out to lunch.
If the conservative base gets itself wound up in this anti-evolutionism, then I hope you're happy when Bush is forced to nominate a squishy moderate or full blown lefty to the court, just because you have wasted our political capital on this useless issue.
And I doubt you will ever understand how much damage you will do to faithful people who will reject their religion because they will refuse to disbelieve the evidence of Evolution they know exists.
All this, because you're convinced that God is too impotent to have thought up and created Evolution.