As part of a project interacting with Sanders pivotal work, Paul and Palestinian Judaism, my thoughts included the following:
One also wonders to what extent the Rabbinic sources of the Tannaitic period reflect the religious praxis of the first century AD in general. In other words, though Rabbis seemed to generally emphasize obedience only after assuming covenantal election, it does not follow that legalistic attitudes could not arise in the daily religious life of the Jew. Orthodoxy, as it were, might not guarantee orthopraxy. It must be recognized that Sanders is initially carrying out a comparative analysis of ancient sources reflecting Judaism from its own perspective. In the end, however, one must weigh both the perspective of the New Testament writings on Judaism (written primarily by Jews!) and the deviations with respect to covenantal nomism in the Jewish (non-New Testament) sources.
Though Dunn and Wright have picked up the slack in this regard, it appears to me that covenantal nomism is virtually assumed by many and applied to Paul. I think there may be more work to do on covenantal nomism as a pattern of religion during Jesus’ and Paul’s respective lifetimes.