Ethnicity and politics: Wilmot Robertson's argument in The Dispossessed Majority is that American politics is basically a conflict between the white majority and a coalition of white minorities and non-whites. What do General Social Survey data tell us about this?
I limited the sample to roughly the top 10% in terms of occupational prestige in order to focus on the most influential people. Here is the ranking of people who identify themselves as Democrat (strong, not strong, independent--near):
East Indians 47.5
American Indians 42.6
(Keep in mind that these numbers do not include independents and members of other parties who are liberal). While you can seen a pattern here of blacks, Jews, and Mexicans at the top, and traditional, large white groups at the bottom--English and Germans--the reality is much messier than Robertson's characterization. First, there is a real split in most groups, so ethnicity is frequently not an important factor. Second, Scots, Danes, and Norwegians should not be on the top half of the list, and the Irish, American Indians, and Chinese should not be on the bottom half, if Robertson were right.
Not only are white groups generally split, but many non-white groups are. And one might expect more conformity among high-status members of ethnic groups, but the numbers shown here still generally show a split.
Now, it might be that the numbers would be a little sharper if we looked at actual voting. The sample sizes are too small for the high-status people in each group, but looking at blacks and Jews, 87.7% of elite blacks and 74.1% of elite Jews voted for Gore in 2000. So looking at voting instead of party affiliation shows a higher number for blacks but not for Jews. I would call 88% a rough consensus, but it's harder to say that about 74%, and we can't say it about any of these other groups. There is indeed a connection between ethnicity and politics, but Robertson exaggerates its importance.