One way to look at it is that the worst that would have come from an honorable campaign would have been a loss at the polls - and that happened anyway.
Update: For example,
By sunrise the next day, it was clear to Romney that they had acted too quickly. The campaign learned that four Americans had been killed in an attack on a U.S. mission in Benghazi, Libya, including Ambassador J. Christopher Stevens. Even to some Republicans, Romney’s hasty statement looked insensitive. “We screwed up, guys,” Romney told aides on a conference call that morning, according to multiple people on the call. “This is not good.” His advisers told him that, if he took back his statement, the neoconservative wing of the party would “take his head off.” He stood by it during an appearance in Florida. Two days later, Obama traveled to Joint Base Andrews to meet the four flag-draped coffins.I have read that when it came to Romneycare in Massachusetts, he responded to similar objections with "I want to do the right thing." Where did that guy go?