Once Mitt Romney has the the nomination completely sewn up, a conservative movement that has been skeptical of him will quickly close ranks behind him and do their damnedest to get him elected president. Whatever lack of enthusiasm the movement’s activists and opinion leaders suffer from will not be at all apparent in their defenses of Romney’s record and credentials.

A vital early job for the party is setting the boundaries of what is and isn’t “fair game” for political attacks. While most negative rhetoric is sort of cheerfully accepted by the objective press and “Village” elders as part of the wonderful game of politics, some lines of attack — like stuff involving children and families and oftentimes health — are...