I never hear conservatives advocate "states's rights". I sometimes hear them support the 9th and 10th amendments to the US Constitution, but these make no mention of states's rights. The 9th refers to rights being retained by the people, and the 10th refers to powers being reserved for the states and the people. Under traditional conservative thinking, states do not have rights. Only the people have rights. A law professor should understand this.
Also, he tries to use ultraconservative as a pejorative word for Ashcroft. But Ashcroft's views on the subject of the essay, enforcement of anti-marijuana laws, are squarely within the mainstream.