[Peter J]
The different is that to say that “a council must be accepted by the laity to be valid” would imply that the laity have a veto power.
The Greek laity did have veto power with the councils of Lyon 2 and Ferrara-Florence,as far as the Eastern Church was concerned. The Greek bishops caved in under pressure from the laity.
(Similarly, if I said “a council must be accepted by the Bishop of Worcester, MA, to be valid” that would imply that the Bishop of Worcester has a veto power.)
No-one ever claimed that the bishops of Antioch or Alexandria or Constantinople had authority over the whole Church,but there are plenty of examples from the writings of clergymen,popes and historians which show that the bishop of Rome had authority over the whole Church. So the bishop of Rome did have the authority to veto a council.
St. Maximos:
“How much more in the case of the clergy and church of the Romans, which from old until now presides over all the churches which are under the sun? Having surely received this canonically, as well as from councils and the apostles, as from the princes of the latter (Peter & Paul), and being numbered in their company, she is subject to no writings or issues in synodical documents, on account of the eminence of her Pontificate …even as all these things all are equally subject to her (the church of Rome) according to sacerdotal law. And so when, without fear, but with all holy and becoming confidence, those ministers (the Popes) are of the truly firm and immovable rock, that is of the most great and Apostolic church of Rome.” (Maximus, in J.B. Mansi, ed. Amplissima Collectio Conciliorum, vol. 10)
St. Nicephorus:
“Without whom (the Romans presiding in the seventh Council) a doctrine brought forward in the Church could not, even though confirmed by canonical decrees and by ecclesiastical usage, ever obtain full approval or currency. For it is they who have had assigned to them the rule in sacred things, and who have received into their hands the dignity of Headship among the Apostles.” (Nicephorus, Niceph. Cpl. pro. s. imag. c 25 [Mai N. Bibl. pp. ii. 30]).
St. Theodore the Studite of Constantinople (759-826), writing to Pope Leo III:
“Since to great Peter Christ our Lord gave the office of Chief Shepherd after entrusting him with the Keys of the Kingdom of Heaven, to Peter or his successor must of necessity every novelty in the Catholic Church be referred.” (Theodore, Bk. I. Ep. 23)
St. Theodore:
“Let him (Patriarch Nicephorus of Constantinople) assemble a synod of those with whom he has been at variance, if it is impossible that representatives of the other patriarchs should be present, a thing which might certainly be if the Emperor should wish the Western Patriarch (the Roman Pope) to be present, to whom is given authority over an ecumenical synod; but let him make peace and union by sending his synodical letters to the prelate of the First See.” (Theodore the Studite, Patr. Graec. 99, 1420)