You'll recall my previous posts (two links there) on Bishop Bruskewitz's decision to excommunicate members of about a dozen groups, including Call to Action and SSPX, en masse. CTA apparently appealed to the Signatura, which declined to rule on the issue. News reports have tended to treat this non-decision as a verification of Bruskewitz's decision, and of Cardinal Re's letter of support to Bruskewitz. Too often such coverage ignores crucial questions of canon law surrounding the excommunication. So, to help flesh out this aspect of the story, here's a provisional interpretation I received from a canon lawyer:

As far as I can see, the Signatura is correct: it has no jurisdiction in merits concerning the legislative act by a diocesan bishop. They just did not decide anything. This ruling is now interpreted in American jurisprudential terms: the court upheld the constitutionality of Bruskewitz's legislation. None of that not in canon law.

Further: the Signatura would have no power to interfere with Re's letter because it was not an act of the Congregation; as far as the evidence goes it was a private letter on the Congregation's letterhead. Since his letter has no legal standing, one can only debate it.

I think the only way to challenge Bruskewitz in canon law would be an action by an individual person who on the basis of Bruskewitz's legislation has been personally (by name) excommunicated judicially.

Even then, the Court would pronounce on the individual case; they would not re-examine the merits of a legislative acts that is based on local facts.

I suspect that Call to Action was steadily counseled by a civil lawyer who tried to follow the American way of legal remedies leading his/her client from one blind alley in canon law into another.

Call to Action and the media also misread the decisions--from what I know not one of the decisions has legally upheld Bruskewitz; they either expressed in a nonlegal way sympathy with his doings or abstained.