Luther didn't defend Catholic Tradition, he was a revolutionary--like the Pontiff. The Archbishop drew the line in the sand--this is Catholic Tradition. If you, the Roman Pontiff, oppose it, however much I may revere your office, I am obliged to resist you and defend the faith. I cannot be complicit in establishing a new religion.
He was defending Scripture - isn't that traditional enough?
Unless I am convinced by Scripture and plain reason — I do not accept the authority of the popes and councils, for they have contradicted each other — my conscience is captive to the Word of God. I cannot and will not recant anything for to go against conscience is neither right nor safe. God help me. Amen.
Christ . . . is the Master of my doctrine . . . it is not mine, but His own pure Gospel. (Against the Falsely So-Called Spiritual Estate of the Pope and Bishops, July 1522)
For inasmuch as I know for certain that I am right, I will be judge above you and above all the angels, as St. Paul says, that whoever does not accept my doctrine cannot be saved. For it is the doctrine of God, and not my doctrine. (Against the Falsely So-Called Spiritual Estate of the Pope and Bishops, July 1522)