Spelling it out further - the problem is that board independence means the ECB can do whatever the heck they care to, short of printing fourteen billion and walking home with one each. Currently what they care to do appears to be  "burn the european economy and project down". Charitably, because they are morons.
Apply all legal measures of persuasion and pressure you can think of until their desires change, and their new course of action is every bit as formally unstoppable.

Once people realize that the ECB is essentially an endrun around the entire formal political structure, the status quo will last.. a month?