So you agree the law exists?
I hardly think it is irrational, or morally incorrect, to desire the law to be enforced. Nor, is it a stretch to be concerned about this issue.
The law in question is CIC 915, which reads only:
“Those who have been excommunicated or interdicted after the imposition or declaration of the penalty and others obstinately persevering in manifest grave sin are not to be admitted to holy communion.” - CIC 915
It is almost never enforced lightly, because of CIC 213:
“The Christian faithful have the right to receive assistance from the sacred pastors out of the spiritual goods of the Church, especially the word of God and the sacraments.” - CIC 213
Only a few applications of CIC 915 have significant Papal authority. For example, Pope John Paul was clear that it applies to Catholics who are divorced and remarried, or married outside the Church (JPII, Ap.Exhort. FC nos. 82, 84; AAS nos. 74, l83, l85; TPS n. 27 [1982] ß 71, 73; PCLT: HCDCRC).
This application also appears to have made it into the 1997 revision of the Universal Catechism (CCC 1650). However, US Bishops have been reluctant to enforce this and Rome has seemingly not pressured them to do so.
The application of CIC 915 in the case of politicians and abortion is new, and not yet clear. The only applications that I am aware of in the US have all come from Archbishop Raymond Leo Burke (previously the Bishop for La Crosse). In those cases, CIC 915 was only invoked after Burke had personallly interceded and attempted to meet directly with each party involve.d
Based on a meeting of the USCCB, Burke’s application was not challenged, but nor was it widely accepted. In the US, it appears only 2-3 Bishops consider such an application appropriate. The guidance from Rome on the matter is a little mixed.
Last year, when visiting Brazil, Pope Benedict appeared to broach the subject of excommunication with regards to politicians voting for less restrictive abortion laws in that country. But this was in news conference, and Benedict’s spokesman, Rev. Federico Lombardi, later clarified the Pope’s remarks, indicating that the Pope had missunderstood the question and the exact situation being asked about.
Direct abortion involves an automatic sentence of excommunication, but voting on abortion is not a moral absolute. Pope John Paul II gave an example of such a vote being licit in EVANGELIUM VITAE. And, even the very conservative Archbishop Burke seems to agree, having issued a statement indicating that one could vote for a pro-choice politician and not commit a mortal sin, if one believed there was a more significant moral issue than abortion was at hand.
However, in his statement, Lombardi did indicate that Benedict believes that politicians voting for more permissive abortion laws “exclude themselves from Communion”. But rather this means that CIC 915 applies, or rather the politicians should not present themselves is something of a question mark. In SACRAMENTUM CARITATIS, Pope Benedict appears to give ammunition for both sides. #83 does mention politicians and Bishops’ responsibility to their flocks, but also mentions moral principles which, as Prefect, then Cardinal Ratzinger wrote do not rise the the level of CIC 915.
So, it seems clear that the Pope’s position that voting for the non-negotiables identified by the Church (the section cites the 9 non negotiables and the Doctrinal Note on voting that I often quote) makes one unworthy to present oneself for communion, but it appears that the Bishops still have some latitude in deciding which votes, if any, rise to the level of CIC 915 for their flocks.
Simililarly #89 is also a little ambigious, both mentioning the Church’s obligations to contributing to a just society, while bringing up Benedict’s own warnings of the dangers of the Church being too assertive politically. Again, it appears that some latitude is given to the Bishops because of differences in local situations.