I enjoy debating Protestants on issues of faith, but every discussion I have with one ends in the same frustrating dead end of doctrinal indifference. This is typified by something a Presbyterian friend said to me, "We believe that accepting Jesus is all that matters, once he is in your heart, we will be debating the finer points of the faith til the day He comes back." This proposition makes any argument moot because it claims that theological debate among Christians can never produce a solid result. My friend's judgement is fairly accurate when applied to Protestant sects, because lacking a Magesterium, Protestants can make no absolute claim to theological truth beyond the most basic of doctrines.
However, this relativism is not satisfactory when considering the differences between Protestantism and Catholicism. Unlike Protestants, the Catholic Church makes a claim of infallibility in matters of faith and morals. The fallibility of Protestant teachings is the very reason for indifference among Protestants and it is unreasonable to be indifferent about competing doctrinal claims when one side declares itself to be infallible. Though Protestants profess indifference about Catholicism, they are not really being indifferent, but implicitly and absolutely rejecting the Catholic Church's claim of authority. Because of this, an honest debate with a Protestant should result not in a declaration of indifference, but a statement of disbelief in the teaching authority of the Church. This is a solid point of contention and should serve as the starting point for a more fruitful debate.