Catechism of the Catholic Church (1994):
1385 To respond to this invitation we must prepare ourselves for so great and so holy a moment. St. Paul urges us to examine our conscience: “Whoever, therefore, eats the bread or drinks the cup of the Lord in an unworthy manner will be guilty of profaning the body and blood of the Lord. Let a man examine himself, and so eat of the bread and drink of the cup. For any one who eats and drinks without discerning the body eats and drinks judgment upon himself.” Anyone conscious of a grave sin must receive the sacrament of Reconciliation before coming to communion.
1395 By the same charity that it enkindles in us, the Eucharist preserves us from future mortal sins. The more we share the life of Christ and progress in his friendship, the more difficult it is to break away from him by mortal sin. The Eucharist is not ordered to the forgiveness of mortal sins—that is proper to the sacrament of Reconciliation. The Eucharist is properly the sacrament of those who are in full communion with the Church.
1401 When, in the Ordinary’s judgment, a grave necessity arises, Catholic ministers may give the sacraments of Eucharist, Penance, and Anointing of the Sick to other Christians not in full communion with the Catholic Church, who ask for them of their own will, provided they give evidence of holding the Catholic faith regarding these sacraments and possess the required dispositions.
USCCB Joint Declaration with the Evangelical Lutheran Church in America , November 4, 2015 (pgs. 114-15):
Next Steps On The Way
Creation of a process and a timetable for addressing remaining issues on church, Eucharist and ministry is clearly an important step forward.The expansion of opportunities for Catholics and Lutherans to receive Holy Communion together would be a significant sign of the path toward unity already traveled and a pledge to continue together on the journey toward full communion.
I think ecumenism has some value, but more of the day-to-day living, shared-burdens-in-the-trenches variety. As a hierarchical endeavor, it has become a totem/idol and all too often acts as the universal (no pun intended) solvent to Catholic coherence.Lutherans and Catholics will continue to advance on the path toward unity by addressing the moral issues that are often deemed [! --Editor] to be church dividing in the same spirit of mutual respect and commitment to unity characterized by their work on issues of justification, church, Eucharist and ministry.
And this dissolving power is recognized and appreciated by those who are most intent on reconstituting Catholic moral theology. How many talking heads at the Synod talked about trying to find common points, shared features between those who follow the teaching and those who conscience it away?
The bottom line: Does being Catholic matter? For the ecumenical directorate, not that much, apparently. Certainly not enough to require anything like honest unity before going unto the altar. Not when you can deem it otherwise.