RIghts as Trumps

From my understanding, Dworkin is arguing that if utilitarianism is to be a practical theory qualifications must be made or else some of our liberties will be infringed upon. Dworkin's answer is that certain rights can trump certain decisions because they infringe on our constitutional liberties. "Indeed, in the absence of an adequate constitutional system, the only hope for justice is precisely that people will vote with a disinterested sense of fairness" (pg 163).

I did have a bit of trouble understanding what "fantastic" meant in terms of Harts' critique. Dworkin summarizes by saying "My hypothesis, that the rights which have traditionally been described as consequences of a general right to liberty are in fact the consequences of equality instead, may in the end prove to be wrong. But it is not, as Hart says it is, 'fantastic'" (pg 167). Did anyone else have trouble with this?