Most of this point is clouded by tedium as to whether or not Calvin was quoted accurately. The quote used contained a typo which causes a rather awkward reading. In this instance, The Romanist is correct on the typo. The typo is in the 1987 TAN reprint on page 293 of O'Hare's Facts About Luther (The worst book on Luther currently available in English). My 1916 edition of this book has the correct quote the Romanist is using on page 299 (the pages numbers are slightly different). Tan Publishers appear to be at fault.
Calvin and Melanchthon were disagreeing on the issues of the will and predestination.... What a shocker.
Here's an interesting excerpt from Calvin's letter to Melanchton:
"This, in all truth, we ought both to seek, viz., to come to an agreement on the pure truth of God. But, to speak candidly, religious scruples prevent me from agreeing with you on this point of doctrine, for you appear to discuss the freedom of the will in too philosophical a manner; and in treating of the doctrine of election, you seem to have no other purpose, save that you may suit yourself to the common feeling of mankind. And it cannot be attributed to hallucination, that you, a man acute and wise, and deeply versed in Scripture, confound the election of God with his promises, which are universal. For nothing is more certain than that the Gospel is addressed to all promiscuously, but that the Spirit of faith is bestowed on the elect alone, by peculiar privilege. The promises are universal. How does it happen, therefore, that their efficacy is no(t) equally felt by all? For this reason, because God does not reveal his arm to all. Indeed, among men but moderately skilled in Scripture, this subject needs not to be discussed, seeing that the promises of the Gospel make offer of the grace of Christ equally to all; and God, by the external call, invites all who are willing to accept of salvation. Faith, also, is a special gift. I think I have clearly expounded this whole question, involved and intricate though it be, in a book but very lately published. Indeed, the matter is so obvious, that no one of sound judgment can [feel] persuaded otherwise, than that you are giving out what is quite different from your real inclination. It increases my anxiety, and at the same time my grief, to see you in this matter to be almost unlike yourself; for I heard, when the whole formula of the agreement of our Church with that of Zurich was laid before you, you instantly seized a pen and erased that sentence which cautiously and prudently makes a distinction between the elect and the reprobate. Which procedure, taking into consideration the mildness of your disposition, not to mention other characteristics, greatly shocked me."
Source: Selected works of John Calvin Vol. 5, p.383-384 (Electronic Version, Ages Digital Sotware)
I think reading the extant material on Calvin and Melanchthon's letters would be an interesting discussion. Of course, I expect almost everyone to disagree with Calvinist theology (on predestination and election, that is). I expect it to cause divisions. I expect it to be offensive. I expect it to cause all sorts of problems. The shocker to me is not that Melancthon and Calvin had differences, the shocker to me is that they still maintained some type of friendship. What an incredible example of Christan brotherhood despite very important disagreements.
You can read some minor dialog I had with the Romanist in his blogback on this subject:here. What I would really like to have is a context for Melanchthon's response to Calvin, which this Romanist posits was : "All the waters of the Elbe would not yield me tears sufficient to weep for the miseries caused by the Reformation." There are only a few letters from Melanchthon to Calvin extant (8 or 9). If anyone has them, or can direct me to a source, I would be very grateful. Why would a disagreement over predestination cause Melanchthon to say this?
In regard to whether the almighty Roman Catholic Church could've helped Calvin and Melanchthon come to agreement on the issue of the Will and Predestination....well... what is the official RCC teaching on Predestination? I recall reading Catholic apologist Art Sippo point out there isn't one: Note the words of Sippo-
"One of the problems we have in catholic apologetics is indeed that there are a variety of positions taken within the Catholic fold on certian key questions. Similarly, there are a variety of positions taken by our prot opponents as well. In some correspondence I had with a "prot controverisalist of my acquiantence" (Pcoma), he complained to me that Gerry Matatics took a different view than I did on predestination. He demanded that I tell him what THE Catholic position was. I tried to explain to him that there was a range of views permissible within the limits of Catholic orthodoxy. Pcoma then complained that it seems our infallible Pope was not able to read the Scriptures and see that it clearly taught Calvinism. I retorted that this particular truth could not currently be reduced to a simplistic formula and quoted some biblical verses that make Calvinism impossible. "