de Wette was the first to suggest that Deuteronomy was the “Book of the Law” that was discovered in the Temple in the time of King Josiah of Judah, as depicted in 2 Kings 22. de Wette ties this “discovery”, which he actually posits as a composition of the text at this time, with the imposition of a degraded Hebraismus on the people: the beginnings of Judaism. Thus, it is not any elaborate philological argument, nor any source critical discovery, nor any kind of argument based upon any logic at all that drives de Wette’s determination of the date of Deuteronomy as late. It is his liberal German Protestantant Romantic nationalist dialectic regarding how degraded Judaism was which determines it. This is in no way objective or acceptable argumentation.
Kevin goes on to completely reject de Wette's conclusions on the basis of his philosophical bias. However, he didn't offer anything in return; no alternative to explaining Deuteronomy and Israelite religion. Kevin asserts that de Wette's conclusions were based on no evidence (aside from perhaps reading the Hebrew Bible which seems to support de Wette's reasoning). The problem is that later archaeology has turned up evidence that supports de Wette, at least in part. De Wette's date for Deuteronomy is generally accepted as the consensus. The connection to Josiah's reform seems likely. The idea of a decline from Mosaic Yahwism to polytheism is generally no longer accepted, though. The early pure religion of Moses is viewed as an idealization of a past that never was. Archaeology supports the assertion that the ancient Israelites were polytheists of a sort, precisely as described in the Deuteronomistic History. Deuteronomy and the Deuteronomistic History together describe the history of Israel precisely along that trajectory of pure Mosaic Yahwism, continual rebellion and idolatry by the people, prophets constantly decrying that idolatry, exile brought as punishment for that rebellion, the return and a re-commitment to the Torah led by Ezra and repentance for rebellion.
So if de Wette was anti-Semitic, should we also conclude that the Deuteronomist and the Deuteronomistic School were anti-Semites? I'm not ready to discard all German biblical scholarship from the 18th-19th centuries on such weak evidence of their anti-Semitism. Kevin, I understand that you're reading a lot on theological anti-Semitism this summer. Just a word of caution, it is popular in ideologically driven scholarship to demonize the opposition by reading between the lines and pulling out philosophical subtexts right and left, imputing motivation and intent. The intentional fallacy should remind us how little access we really have to what they were thinking at the time.