With regard to admission to the sacraments [of those in invalid marriages], the
local Ordinaries are asked on the one hand to stress observance of current
discipline and, on the other hand, to take care that pastoral ministers exercise
special care to seek out those who are living in an irregular union by applying
to the solution of such cases, in addition to other right means, the Church’s
approved practice in the internal forum.
(SCDF, letter, Apr. 11, 1973; CLD
2. The “approved practice of the Church in the internal forum” means: These couples may be allowed to receive the sacraments on two conditions[:],
 that they try to live according to the demands of Christian moral principles, and
 that they receive the sacraments in churches in which they are not known so that they will not create any scandal. (SCDF, letter, Mar. 21, 1975, CLD 9:504-5)
It is preferable that marriage cases be handled in the external forum by means of a process of annulment or dissolution. Under certain conditions, however, canonists and moral theologians have taught that couples living in an irregular second union can approach the sacraments by means of the internal forum solution. Since this is a very involved subject and not strictly a canonical matter, the reader is referred to several articles where a more adequate treatment is developed.
(N.B. All of these articles were published prior to 1995, and therefore advocate a practice that is no longer, for the most part, approved).
James H. Provost, “Intolerable Marriage Situations Revisited,” The Jurist 40 (1980) 141-96;
James J. Young, Ministering to the Divorced Catholic (N.Y.: Paulist, 1979), especially the articles by Richard A. McCormick, Karl Lehmann, and Thomas J. Green;
“Report of the Canon Law Society of America’s Committee on Alternatives to Tribunal Procedures,” in James J. Young, ed., Divorce Ministry and the Marriage Tribunal (N.Y.: Paulist, 1982) 117-39;
John Huels, “The Eucharist and the Divorced and Remarried,” Emmanuel 91 (1985) 268-75.
* John M. Huels, O.S.M., J.C.D., The Pastoral Companion, Quincy, ILL., Franciscan Press, 1986, pp.260-261 (But see his 2nd edition printed in 1995, pp.294-295)
Bibliography of Books and Articles on The Good Faith Solution Basset, William, The Bond of Marriage, Univ. of Notre Dame Press, 1968. Bresnahan, James F., “Problems of Marriage and Divorce,” America, May 25, 1968, pp. 706-709.
Carey, Raymond G., “The Good Faith Solution,” The Jurist, Vol. XXIX, Oct. 1969.
Catoir, John T., “Church and Second Marriages,” Commonweal, April 14, 1967, p. 113. “What is the Marriage Contract?” America, Vol. 118, no. 7, p. 229.
Constitution on the Church in the Modern World, nos. 12, 17.
Council Daybook, Vatican It Session 4, pp. 71-72, An Address by Archbishop Elie Zoghbi.
Doherty, Denis, “Problem of Divorce and Remarriage,” Marriage 28, 1966, pp. 12-18.
Haring, Bernard, The Law of Christ, Newman Press, 1966, Vol. III, p. 327. Hertel, James R., O.D.M., When Marriage Fails, Paulist Press, Paramus, N. J.
Hertel, James, “Save the Bond or Save the Person,” America, Vol. 118, n. 7, Feb. 17, 1968, pp. 217-220.
Hurley, M., S.J., “Christ and Divorce,” Irish Theol. Quarterly 35, 1968, pp. 58-72.
“Indissolubility of Marriage, The,” The Theological Tradition of the East, pp. 97-116.
Kelleher, S.J., “The Problem of the Intolerable Marriage,” America, September 14, 1968, pp. 178-182.
Krebs, A. V., “American Catholic Marriage and the Church,” America, Feb. 1969, p. 228.
Mahoney, John, “Do They Intend Marriage,” HPR, 67, 1966.
Monden, Louis, S.J., Sin, Liberty and Law, Sheed dr Ward, N.Y. 1965, pp. 135-136.
Montserrat, J. - Torrents, The Abandoned Spouse, Bruce, 1969. Pope John XXIII, Pacem in Terris, no. 58.
Pospishil, Victor J., Divorce and Remarriage, Herder and Herder, N.Y., 1967, pp. 40-73. / “The Damned Millions: The Problem of Divorced Catholics,” HPR, 1968, pp. 95-104.
“Sacraments: An Ecumenical Dilemma, The,” Concilium 24, Paulist Press, N.Y., 1967, pp. 113-138.
Shaner, Donal, A Christian View on Divorce, E. J. Brill 1969, Leiden, pp. 14-25.
Sullivan, Jos. Deuel, “Divorce and Psychological Change,” Cath. Theol. Soc. of America Proceedings, Vol. 22, 1967, pp. 245-252.
The Jurist, January 1970 contains these excellent articles:
(1) “Intolerable Marriage Situations: The Conflict between the External and Internal Forum,” by Ladislas Orsy, S.J.
(2) “Law, Conscience and Marriage,” by Peter Huizing.
(3) “Internal Forum Solutions to Insoluble Marriage Cases,” by Bernard Hiring.
(4) “The Pastoral Care of Those Involved in Canonically Invalid Marriages,” by Anthony Kosnik.
(5) “Toward ‘An Immediate Internal Forum Solution’ For Deserving Couples in Canonically Insoluble Marriage Cases,” by Leo C. Farley and Warren T. Reich, S.J.
“The Tragedy of Broken Marriages,” Jubilee, March 1966, p. 48.
CANON LAW DIGEST, 8:631-2:
SCDF, letters of April 11, 1973
Indissolubility of Marriage : New Opinions (S.C. Doct. Fid .,11 April, 1973) Private.
The following letter was addressed to the local Ordinaries.
This Sacred Congregation, which has the responsibility of safeguarding doctrine of faith and of morals in the whole Catholic world, with watchful concern is observing the diffusion of new opinions which either deny or are making efforts to call into question the doctrine constantly set forth by the Church' s magisterium on the indissolubility of marriage.
Opinions of this kind are propagated not only by writings in Catholic books and periodicals but also in seminaries and Catholic schools. Moreover, they are beginning to work their way into the very praxis of some ecclesiastical tribunals in this or that diocese.
Furthermore, such opinions conjoined with various doctrinal or pastoral reasons, are taken as a starting point for an argument to justify abuses contrary to the prevailing discipline regarding admission to the sacraments on the part of those who are living in an irregular union.
As a consequence, this Sacred Department, in its plenary session in 1972, subjected the matter to examination as a result of which it was ordered, with the approval of the Supreme Pontiff, to exhort Your Excellency earnestly to diligent vigilance so that all those who are entrusted with the assignment of teaching religion in schools of whatever level or in institutes or with the assignment of chief judge (officialis) in an ecclesiastical tribunal remain faithful to the Church's doctrine on the indissolubility of marriage and put it into practice in ecclesiastical tribunals.
With regard to admission to sacraments, the local Ordinaries will also please, on the one hand, stress observance of the current discipline of the Church while, on the other hand, take care that pastors of souls follow up with particular solicitude those who are living in an irregular union and, in such cases, in addition to other correct means, use the approved practice of the Church in the internal forum.
(Private) ; S . C . Doct . Fid ., letter, 11 April, 1973, Prot . N Prot . N . 1284/66, 139/69 ; copy furnished by the Canadian Canon Law Society.
CANON LAW DIGEST, 9:503-5:SCDF,
letter, April 11, 1973 and March 21, 1975.
Letter of the Prefect of the S.C. for the Doctrine of the Faith
This Sacred Congregation, whose duty it is to safeguard doctrine on faith and morals throughout the Catholic world, is observing with vigilant care the diffusion of new opinions which either deny or attempt to call into question the teaching constantly proposed by the Magisterium of the Church on the indissolubility of marriage.
Opinions of this kind are not only being propagated in writing in Catholic books and periodicals, but are also beginning to worm their way into seminaries and Catholic schools as well as into the very practice of some ecclesiastical tribunals in this or that diocese.
Further, such opinions, together with other doctrinal or pastoral reasons, are here and there taken up as an argument to justify abuses against the prevailing discipline concerning the admission to the sacraments of those who are living in an irregular union.
Consequently, this Sacred Dicastery in its plenary session of 1972 subjected the matter to examination. A mandate was received from it and approved by the Supreme Pontiff to urge Your Excellency strongly to diligent vigilance so that all those who have been entrusted with the task of teaching religion in schools of whatever level or in institutes, or who [p.504] function as officialis in an ecclesiastical tribunal, may remain true to the doctrine of the Church regarding the indissolubility of marriage and reduce it to practice in ecclesiastical tribunals.
As regards admission to the sacraments, the local Ordinaries will likewise please urge observance of the prevailing discipline of the Church on the one hand, and, on the other hand, however, take care that pastors of souls follow up with special solicitude those also who are living in an irregular union, applying in the solution of such cases, in addition to other correct means, the approved practice of the Church in the internal forum.
(Private); S. C. Doct. Fid., letter, 11 April, 1973, Prot. NN. 1284/66 and 139/69; copy of the Latin text kindly sent us by the General Secretary of N.C.C.B.
Letter of the Secretary of the S. C. for the Doctrine of the Faith to the President (Archbishop Bernardin) of N.C.C.B.
As you reminded us in your recent letter of December 31, 1974, and also during your visit of March 11, Cardinal Krol, when he was President of the National Conference of Catholic Bishops, wrote to this Sacred Congregation requesting an official interpretation of the phrase used in the circular letter of April 11, 1973, “probata praxis Ecclesiae.” [approved practice of the Church] This phrase referred to Catholics living in irregular marital unions.
First, I want to express my keen regret in having made your Conference wait so long for a reply to your letter.
I would like to state now that this phrase must be understood in the context of traditional moral theology. [p.505] These couples may be allowed to receive the sacraments on two conditions,
that they try to live according to the demands of Christian moral principles,
and that they receive the sacraments in churches in which they are not known so that they will not create any scandal.
(Private); Secretary of S.C. Doct. Fid., letter, 21 March, 1975, Prot. N. 1284/66; original English text; copy kindly sent us by the General Secretary of N.C.C.B.
 “approved practice of the Church”; see last sentence of the immediately preceding document.