Forewords: I'm not associated, in any way, with the party I'm going to ask about.
I simply proposed an edit to a question, and it's not a huge deal (it could be easily refused) but it made me wonder: why someone should decide to translate the proper noun of a foreigner party, and what is the general consensus on it?
In the question I'm referring to, the name Movimento Cinque Stelle (which, I stress again, it's a proper brand noun, like Facebook or Michigan or Ferrari) is been translated with Five Star Movement, which is something which AFAIK does not exists, even if it seems en.Wikipedia too has decided to call it that way.
So, what should be the general rule for the group? I find it confusing, tbh, 'cause even in "real life" some parties are translated, some are not, and not only in English but in other languages as well...