What does one do when a very good defender of Romanist doctrines poses arguments that seem legitimate, and one is not able to answer them?

We have built a library of works (concentrated on the 1600’s) that systematically refute Romanism doctrine by doctrine in order that you can quickly skim through them, find your subject matter, and find in-depth, reformed, catholic, material refuting that exact point of Romanism, no matter how minute:

Romanism

Is the Roman Church, though apostate, a part of Christ’s visible Church?  Is the Roman ministry and Romish baptism valid?  There is immense confusion on these questions today, with many coming to the wrong answer.

The near-universal reformed consensus during the Reformation and puritan eras to these questions was ‘Yes’.  Find out the Biblical reasons for this.  The established Reformed Church largely defended the validity of her ministers on the validity of the Roman Church being a Church.  Yet they also were convicted that the Protestant separation from Romanism was morally and Scripturally necessary.

And lastly, may Romanists be saved?  Read the classic reformed answers to these questions on this new page.  See especially the Intro and the writings of Samuel Rutherford:

On the Roman Catholic Church being a Church, her Baptism being Valid, that the Reformers’ Ministerial Calling was Valid, the Necessity of Separation from Her & Whether Romanists may be Saved