The point is, you cannot use the vast cumulative output of the popes to look for statements that infallibly deny infallibility, as you attempted.
I do not think the dual procession of the Holy Ghost has been defined infallibly. Further movement on this doctrine is possible, and, given some intriguing passages in the recent Deus Caritas Est, likely.
"I do not think the dual procession of the Holy Ghost has been defined infallibly."
Sure it was, at Nicea, Alex. But that doesn't end the discussion, AMHN. Where the problem has been for the past 1000 years or so has been with the West's own, often theological and hierarchial if not papal, attempts to justify filioque with novel theology. The understanding of the procession of the Holy Spirit in the East has always been as stated by +Gregory Palamas in the 13th century:
"The Spirit of the supreme Logos is a kind of ineffable yet intense longing or 'eros' experienced by the Begetter for the Logos born ineffably from Him, a longing experienced also by the beloved Logos and Son of the Father for His Begetter; but the Logos possesses this love by virtue of the fact that it comes from the Father in the very act through which He comes from the Father, and it resides co-naturally in Him.
It is from the Logos's discourse with us through His incarnation that we have learned what is the name of the Spirit's distinct mode of coming to be from the Father and that the Spirit belongs not only to the Father but also to the Logos. For He says 'the Spirit of Truth, who proceeds from the Father' (John 15:26), so that we may know that from the Father comes not solely the Logos - who is begotten from the Father - but also the Spirit who proceeds from the Father. Yet the Spirit belongs also to the Son, who receives Him from the Father as the Spirit of Truth, Wisdom and Logos. For Truth and Wisdom constitute a Logos that befits His Begetter, a Logos that rejoices with the Father as the Father rejoices in Him.
This accords with the words that He spoke through Solomon:'I was She who rejoiced together with Him' (Prov. 8:30). Solomon did not say simply 'rejoiced' but 'rejoiced together with'. This pre-eternal rejoicing of the Father and the Son is the Holy Spirit who, as I said, is common to both, which explains why He is sent from both to those who are worthy. Yet the Spirit has His existence from the Father alone, and hence He proceeds as regards His existence only from the Father. Our intellect, because created in God's image, possesses likewise the image of this sublime Eros or intense longing - an image expressed in the love experienced by the intellect for the spiritual knowledge that originates from it and continually abides in it."
So far as I know, and I base this on the comments of the Roman and Orthodox theologians who together came up with an agreed statement on the Creed, this is the precise and correct meaning of the filioque for Roman Catholicism. Thus the Roman Church has apparently agreed that the Creed without the filioque is "normative" and should be what is used for translations and catechesis.
The filioque started out as an attempt to counter Arianism. Its imposition on the Church by Rome was at a minimum misguided and I think, AMHN, you may be right that it at least in part lies at the base of medieval claims of papal supremacy. Remember that in the False Union of Florence, Orthodoxy was not required to accept the filioque. By the time of the Reformation, Rome had reason to harden its positions about papal supremacy, but they weren't cvoming from the East.
Frankly, AMHN, the filioque is only an issue if Rome insists on a dual procession of the HS...and if it really ever did, it doesn't now.