One question with which I've wrestled as I've thought about my Fishbane paper is this: when did Israel's traditions become an authoritative traditum?
I'm not in the mood right now to sort out what Fishbane believes about that, though it will be a necessary endeavor before I write the paper. He seems to believe that certain traditions were regarded as authoritative prior to the exile, since there are people who try to interpret, apply, and contemporize them at that time. Yet, there are also authors who insert things into the text or disagree with the traditum, so it's not inflexible, rigid, and unquestioned by everyone.
Martin S. Jaffee's Early Judaism (New Jersey: Prentice Hall, 1997) provides a history of canonization (70-71). He doesn't really substantiate what he's saying, but his model offers food for thought.
According to Jaffee, in 1000-587 B.C.E, Israel had oral and written traditions, which contained stories and laws. In 539-323 B.C.E., it selected from those traditions and placed certain ones in a Torah of Moses. At that time, prophetic oracles, psalms, and proverbs were also compiled, and histories were either completed (in the case of Joshua-Kings) or composed (as was the case with Chronicles and Ezra-Nehemiah). Within 323-63 B.C.E., Esther, Ruth, Job, Ecclesiastes, the Song of Songs, and Daniel were written, and Jubilees competed with the Torah for authoritative status.
I agree that there was something authoritative in the pre-exilic period, since the prophets refer to a law (though I may not state this dogmatically in my paper, since I think my professor dates the prophets a little late). But it may not have been the case that there was one law governing all of Israel. The priestly traditions distinguish between the sons of Aaron and the Levites. The Deuteronomist, by contrast, treats all the Levites as equal. Ezekiel tends to go with the former school, whereas Jeremiah has more affinity with the Deuteronomist. That confuses me. Which law governed all of Israel? Both prophets act like their versions do--or at least that the authorities should follow their versions.
If the Torah was being put together in the post-exilic period, then I can understand why there may have been disagreement with it. Maybe these traditions were new to some people. Or another possibility is that some thought God would work in different ways after the exile. God may have excluded certain Gentiles in the past, but that doesn't mean he has to act the same way in the future. Jeremiah 31, for example, describes God doing new things, different from what he did in the past.
I wonder how there could be competition about Scriptural status in the Hellenistic period. Was Jubilees a marginal book? Jaffee struggles with this issue (73-78). We're lucky to have found the book, yet it does crop up in the Dead Sea Scrolls. Did most Jews accept the "Torah," while a few pawned off alternatives to it? I don't know.