"clearly defined" and "EU law" seldom go well together :)

Excellent point. For procedural reasons, there wouldn't be any consequence to a violation of institutional balance, anyway. When the man with a Treaty meets the man with political cover...

Of course, the problem remains: is a stament of an "EU leader" (regarding international politics) necessarily made on behalf of the EU? I think so, but i might be wrong. Any suggestion would be welcome!

NB: the Commission is the default EU representative, ex art. 17(1) TEU. Others speak for the EU only where Treaties explicitly introduce derogations to the rule (e.g., CFSP)

Sure, as i mentioned, i think that neither President can make a statement without some grounding in a Council position. Possibly, this particular statement is understood as sui generis in political terms. But, of course, that does not solve the legal problems per se.

All valid points. I understand that the HR, in particular, makes hundreds of "HR statements," each year. But they are interpreted as EU positions. And, in principle, should be based on the EU established position. That's why i wonder whether the COM Pres' statements should follow a different rule

E.g. Ukraine, Palestine, and defence policy. As well as migration, in certain respects (see the memorandum with Tunisia).

I am not aware of a systematic practice that contradicts this interpretation, but if you have any suggestion regarding other leaders' statements on international issues (not corresponding to EU established policy), I would be very grateful!

From a logical standpoint, the same approach should be applied to the EU Commission President's statements, as she, when acting in her official capacity, exercises the Commission powers, notably the power of external representation

It's an interesting point. It is my understanding that, according to established Commission (and Council) policy, one cannot distinguish between "Commission" and "EU" positions about international issues because the Commission is, by default, the EU external representative.

You're righ, this specific crisis is facilitating institutional evolution. But there's also an aggressive approach on the part of this Commission's leader(s), in different policy areas. One can possibly see it as a welcome development but I doubt it is unavoidable

Such a casual disregard for institutional balance has increasingly become the norm under von der Leyen. With almost no consequence, so far.