In another subreddit, we were discussing the nature of the relationship between the Nazis and the Roman Catholic Church.
Another Redditor stated that
It's actually believed that a pretty significant portion of Nazis were excommunicated.
- and linked to an article saying that
The New-York based Pave the Way Foundation said that its representative Michael Hesemann found a large series of documents from 1930 to 1933.
The documents indicate that any Catholic who joined the Nazi party, wore the uniform or flew the swastika flag would no longer be able to receive the sacraments. ...
"Michael Hesemann has been diligent in researching the open archives and has been discovering new important documents with every visit," he said. "His research tells a very different story of Eugenio Pacelli or Pope Pius XII than is commonly known."
When asked why this information is not currently known by many historians, Pave the Way chairman Elliot Hershberg noted that "according to the archives sign-in sheets, most of these historians and scholars have simply not come to the open archives to research 65% of Pacelli’s ministry.”
http://www.zenit.org/en/articles/archives-show-church-excommunicated-nazis
(I'm not familiar with Pave the Way Foundation - here's their website -
http://www.ptwf.org/index.php?option=com_content&view=article&id=104&Itemid=513 )
Taking a quick look at sources online that talk about the relationship between the Nazis and the Roman Catholic Church, of course these sources make widely varying claims about interpretation and even about the facts of the matter.
So:
Did the Roman Catholic Church excommunicate "a pretty significant portion" of Nazis?
From 1930 (February 7 to be precise) to 1933 (and after that), Eugenio Pacelli was Cardinal Secretary of State for the Vatican under the pontificate of Pius XI. So far as I understand that office and Pacelli's history, it would not have been that office that issued excommunications--at least not in the formal ferendae sententiae sense. A latae sententiae excommunication occurs when the offense is committed and requires no action from the Church. The person basically excommunicates themselves (which is an oversimplification, but we're dealing with a complex topic here). Pacelli as Cardinal Secretary of State would have little to do with either category.
To research this (which I have not) one would have to have access to the archives of Pius XI from the period to find instances of ferendae sententiae excommunication, and this would have to be buttressed by investigations of the archives of the German bishops in whose jurisdiction the excommunications would have occurred within. For the latae sententiae excommunications, one would need to find an expert in the 1917 Code of Canon Law (replaced in 1983, so an expert in current Canon Law would not necessarily be sufficient) and an intimate knowledge of the conduct of the people in question. I have not seen this research accomplished as of yet.
Most historians credit Pacelli for writing Mit Brennender Sorge, the 1937 encyclical issued by Pius XI. It features the following assertion in section 8:
Whoever exalts race, or the people, or the State, or a particular form of State, or the depositories of power, or any other fundamental value of the human community - however necessary and honorable be their function in worldly things - whoever raises these notions above their standard value and divinizes them to an idolatrous level, distorts and perverts an order of the world planned and created by God; he is far from the true faith in God and from the concept of life which that faith upholds.
Here is my longer analysis of the encyclical
Finally, it should be noted that excommunication is not a punishment in Catholicism. It is intended to get the person to change their behavior so they can rejoin the Church.
There is a single book that I can unreservedly recommend on Pius XII: Ventresca's Soldier of Christ. If you are interested in the subject that is the place to start. For my own analysis there is my post on Pius XII during WWII.
As always, followup questions from OP and others are encouraged.
The documents indicate that any Catholic who joined the Nazi party, wore the uniform or flew the swastika flag would no longer be able to receive the sacraments. ...
Banning receipt of the sacraments is an interdict, not an excommunication. While many of the punishments are similar, the interdict is not a complete removal of the Catholic community like an excommunication is.
Though I do not know how or it this would have been applied to Nazi's.