Such a lie is permissible because it is the lesser of two evils. Lie or allow an innocent person to be murdered.
The analogy fails here because Roberts can say that while he dutifully adheres to Catholic teaching, the Church teaches that he shouldn't impose particularly Catholic teachings on non-Catholics. Moreover, Church teachings require that his rulings not violate the natural law, a law written on the human heart which is not exclusive to Catholics, Christians or theists of any religion.
That said, it gets a little dicey because he took an oath to testify truthfully. Does the unentitlement to truth trump the oath?
It may be permissible to duck the question, although I don't see the issue as a loser at all. It would be a great opportunity to create a public debate regarding natural law and abortion.
But effectively saying that he won't be a slave to Church teaching is a very grave lie, if it is a lie, or woeful ignorance of Church teaching.
I'm looking for a silver lining, I admit.
I know. I want an orthodox Catholic in there too. But I'm not seeing it right now.
Then that would pretty much make it impossible for a practicing Catholic to hold any political office.
The sin of abortion is one of the few that are considered intrinsically evil by our church, however, we don't own the copyright to the pro-life movement, either. One need not be Catholic to oppose abortion, so opposing abortion doesn't have to imply an overriding loyalty to Rome.
Roberts said he never turned down a request for pro bono work while in private practice, including a case on gay rights. "I think it's right that if there had been something morally objectionable, I suppose I would have."