Canon 455
#1 A conference of bishops can only issue general decrees in cases where universal law has prescribed it or a special mandate of the Apostolic See has established it either motu proprio or at the request of the conference of bishops.
#2 The decrees mentioned in #1, in order to be enacted validly in a plenary meeting, must be passed by at least two thirds vote of the prelates who belong to the conference and possess a deliberative vote. They do not obtain binding force unless they have been legitimately promulgated after having been reviewed by the Apostolic See.
#4 In cases in which neither universal law nor a special mandate of the Apostolic See has granted the power in #1 to a conference of bishops, the competence of each diocesan bishop remains intact, nor is a conference or its president able to act in the name of all bishops unless each and every bishop has given consent.
Thank you. Fortunately, it doesn’t really sound as if these national conferences have much power on their own. Of course, I guess they have the power of simply existing and babbling to the press to make it sound as if they have a lot of other powers.