The recent research in these areas thus gives powerful confirmation to hypotheses that only a few interpreters were previously ready to entertain and willing to argue. First, Israelite culture was as diverse as were the groups and communities that comprised Judean, Galilean, and Samaritan society. Different versions of Israelite tradition coexisted and competed. The well-known differences between the Sadducees and the Pharisees can be multiplied. (Horsley, Jesus in Context, 129)
This is true, for the most part. But again I'm a little frustrated that Horsley rails so effectively against established assumptions even while continuing to employ them. Earlier on page 129, for example, Horsley has rightly noted:
[T]hose who have closely examined the multiple scrolls of books of the Torah found at Qumran are also concluding that the text of the books of the Torah was not yet uniform or stable. Different textual traditions still existed in the same scribal community (and presumably in Jerusalem as well), each of which was still undergoing development. The Dead Sea Scrolls also supply further examples of alternative Torah (4QMMT; the Temple Scroll) and alternative versions of Israelite history and tradition (not rewritten Bible; Jubilees; Pseudo-Philo, Biblical Antiquities) that coexisted and competed, at least among scribal circles.
Some conservative Christians, somehow, turned to the DSS (and especially the Great Isaiah Scroll) in order to argue for the textual stability of the Hebrew Bible even in texts that were 1,000 years older [!] than previously known texts. Some texts were indeed remarkably similar to what became the Masoretic Text (the basis for modern English translations of the Old Testament), but others were strikingly different. And there were also other texts that Jews and Christians would later exclude from the canon. None of this is meant to imply the Bible is unreliable or untrustworthy. But if the DSS have any significance for the question of the Bible's reliability, that significance is very ambiguous.
Horsley, however, has recognized the textual and traditional dynamics at play at Qumran even while adhering an old paradigm of "competing versions." Qumran might not have preserved a stable text-form of Hebrew biblical traditions, but neither does it suggest a competition between text-forms. In fact, if competition were the best way to think about different text-forms (LXX, MT, Samaritan, in addition to various minor and other variant readings and traditions), I would expect Qumran to have expended some effort to conform their biblical scrolls to a particular text-form.
Instead, we find at Qumran evidence that LXX, MT, and Samaritan readings could be preserved and read as authoritative in a single community. This isn't competition. Rather, it suggests that the text-form may not have been the most important factor. What mattered, I suggest, was the tradition itself, and the text's primary significance was for enabling access to the tradition. In this paradigm, then, what matters isn't [necessarily] whether or not this or that reading was preserved but rather how the text functioned to connect the community to its traditions. Of course, specific readings could become significant as groups engaged in social conflict (whether Qumran against a Temple priesthood, or Justin against Trypho, or Samaritans against Judeans, etc.). But even this "becoming significant" was a function of other, extratextual factors.