I love St. Alphonsus Ligouri, but he unintentionally marks the height of the "manuals" of moral theology which focused on the rules and were primarily developed for confessors to determine what was a sin and its gravity, which then helped to assign appropriate penances. It really wasn't a book to help priests catechize and exhort to the virtuous life. Compare this to the moral theology section of the Catechism, which means to cite Ligouri as an example in order to deal with this remedy is a bit problematic. We have moved away from his approach. As to there being "arguments from the tradition" for Cardinal Kasper's apparent desire to admit in some way the divorce and civilly remarried to the sacrament of Holy Communion without compromising doctrine on marriage and the Eucharist, that means a few things, and I would suggest that there are arguments in the tradition, yes, but a proposed remedy would firstly compromise the belief shared by the faithful because it would be founded on a cherry-picking of theology and practice over the last two millennia.
As to the need to not return without any intention of change... I think it is sincerely possible for one to earnestly wish to live as brother and sister with a spouse, one of whom (or both) is actually married to another, and even to believe that this is possible by God's grace without either of them falling into mortal sin. Firstly, all is possible by grace, and second, it is possible for all the baptized to go without mortal sin as dogmatically declared by the Council of Trent. I would think that it is right to say that by grace, one can keep out of further mortal sin. And, if one does fall and have relations with their "spouse," then they need to go to Confession again. I think it poses long-term problems if the elephant in the room, namely that of really being married to another and therefore not having relations with the one presented as your spouse, is left unresolved. (At that point perhaps it's best to split from both parties. Or not, I don't know.)
And the biggie: first, shooting off the Holy Father's belief without context is a problem, and it is compounded by the Holy See Press Office's odd way of dealing with these sorts of incidents. Second, that's a HUGE problem and would be the largest sacramental crisis in history (the non-Baptisms in Brisbane pale, I think). A few points: marriage enjoys the favor of the law. One does not prove the validity of marriage, and even non-consummation doesn't render it invalid. Now, it's a further sign of its validity and it's a further way to perform the sacrament (in a nutshell), but one can be validly married and not ever engage in conjugal relations (a Josephite marriage).
And from Dr. Peters's comments on Facebook:
If marriage is something so difficult to confect that half of all marriages are in fact not marriages, then it makes a mockery of the whole sacrament. Why would Christ institute a sacrament that was so difficult to achieve?The surety of the Church in her judgments and sacraments is a sign of her divine institution, and I add that it is a mockery of that. It injures our understanding of the Church, and I believe it is reflective of the certainty in the uncertainty of reality prevalent in most of contemporary thought from which this alleged belief stems. Also, I think that no one would wind up getting married (even if they tried and actually appeared to be married sacramentally) under some of the proposed reforms because it would basically make our understanding of validity so convoluted and so hard to understand for the spouses, the sacred minister, and later, the tribunal. I think this goes to Christ's promise to the first bishop of Rome, the Prince of the Apostles, His Vicar on this earth. Upon Peter the Church was built, and to him were given the keys to the Kingdom of Heaven, with which come the power to bind and loose on earth and so it shall be in Heaven. And the gates of Hell shall never prevail against her, our most Holy Mother the Church.
To be continued...