The nearest equivelant in Abbott's past of allegations of wrongdoing are sexual harrassment allegations when he was a uni student. They were inquired into and should be left alone. More general issues related to his association with the Church or misogynist views are fair political game. As are past associations of Gillard with the union movement, communist groups etc (if she had involvement). There's no problem with a politician's past being examined, unless it's to smear in regard to allegations already dealt with.
