I will continue with the other questions that I listed in my first post.
2) Should the Church deny Holy Communion to such a politician because of his public stance against her teachings? The Churchs duty to deny Holy Communion in certain circumstances is outlined in the Code of Canon Law.
Code of Canon Law:
Can. 915 Those upon whom the penalty of excommunication or interdict has been imposed or declared, and others who obstinately persist in manifest grave sin, are not to be admitted to holy communion.
St. Thomas Aquinas also addresses this point in the Summa Theologica.
St. Thomas Aquinas, Summa Theologica, Third Part, Question 80, Article 6:
I answer that, A distinction must be made among sinners: some are secret; others are notorious, either from evidence of the fact, as public usurers, or public robbers, or from being denounced as evil men by some ecclesiastical or civil tribunal. Therefore Holy Communion ought not to be given to open sinners when they ask for it.
Canon 915 applies to pro-abortion politicians because they meet the three requirements set forth. The gravity of the sin as already been addressed. Their sin is manifest, because by nature of their office, their voting record is public. Furthermore, with the recent publicity regarding this matter and the press releases by many of the offending parties, it is hard to image a case in which the sin could be more open, manifest, and public. A person would be considered obstinate in persisting in their sin if while being aware of the Churchs condemnation of the act, continue in it. Pro-Life groups such as American Life League and Human Life International have taken considerable initiative in contacting offending politicians and making the Churchs position perfectly clear. To determine obstinacy, we may also look at a politicians record over time.
Should the Church deny Holy Communion to such a politician because of his public stance against her teachings? Yes. This interpretation of Canon 915 is supported by the Holy See as is clear from a press conference held by Francis Cardinal Arinze, head of the Congregation for Divine Worship and the Discipline of the Sacraments, in April of 2004 at which he said that politicians that are clearly pro-abortion should be denied Holy Communion and also from a private communication sent by Josef Cardinal Ratzinger, head of the Congregation for the Doctrine of the Faith, to Theodore Cardinal McCarrick of Washington D.C. in July of 2004. The following is a brief quote of that communication:
5. Regarding the grave sin of abortion or euthanasia, when a persons formal cooperation becomes manifest (understood, in the case of a Catholic politician, as his consistently campaigning and voting for permissive abortion and euthanasia laws), his Pastor should meet with him, instructing him about the Churchs teaching, informing him that he is not to present himself for Holy Communion until he brings to an end the objective situation of sin, and warning him that he will otherwise be denied the Eucharist.
6. When these precautionary measures have not had their effect or in which they were not possible, and the person in question, with obstinate persistence, still presents himself to receive the Holy Eucharist, the minister of Holy Communion must refuse to distribute it (cf. Pontifical Council for Legislative Texts Declaration Holy Communion and Divorced, Civilly Remarried Catholics [2000], nos. 3-4). This decision, properly speaking, is not a sanction or a penalty. Nor is the minister of Holy Communion passing judgement on the persons subjective guilt, but rather is reacting to the persons public unworthiness to receive Holy Communion due to an objective situation of sin.
3) Who should make the decision to deny Holy Communion to such a person if they are not publicly excommunicated? A person could argue that an individual priest should not make the decision of whether or not to deny certain persons the reception of the Blessed Sacrament, but that he should only act if instructed to do so by his local Ordinary. In his promulgation of the New Code of Canon Law, Pope John Paul II wrote: In promulgating this Code today, therefore, we are fully conscious that this act stems from our pontifical authority itself, and so assumes a primatial nature. Further on in the same Apostolic Constitution he wrote: Finally, canonical laws by their very nature demand observance. For this reason, the greatest care has been taken that during the long preparation of the Code there should be an accurate expression of the norms and that they should depend upon a sound juridical, canonical and theological foundation.
As Pope John Paul II stated in his promulgation of the New Code of Canon Law, the laws set forth demand observance. Thus Canon Law is binding on ministers of Communion without prior approval of the Local Ordinary. Canon Law does not require the approval of the Local Ordinary, but is promulgated by pontifical authority. Thus the minister of Holy Communion is obliged to follow Canon Law which explicitly states that obstinate manifest grave sinners are to be denied Holy Communion.
Who should make the decision to deny Holy Communion to such a person if they are not publicly excommunicated? The minister of Holy Communion must make this decision for he is bound by Canon Law to act (or not to act as the case may be). However, the Local Ordinary should certainly see to it that this canon is being implemented, and his public affirmation of this application of Canon Law is to be desired.