Don’t be so sure.
McCain is in his 70’s. If an extreme pro-death candidate, like Hillary is on the left, many evangelicals will see him as the better of two evils.
I hope if McCain is nominated, he at least picks a younger qualified VP because I doubt he makes it 4 years, let alone 8. As far as evangelicals, they will sit home in record numbers, just as they did prior to Ronald Reagan’s campaign. The leftist GOP leadership has fractured the party beyond repair in 2008.