Now, both are doubtless bad to some extent.  As another commenter asked, what if we swapped the population of a 'good' school with an equivalent number from Detroit?  I content that the results would swap as well.  Yes, the schools in Detroit are bad, but parents in Grosse Pointe would never tolerate the situation in Detroit if it were in their schools.

Nobody has mentioned that the real free-market approach to education is to eliminate government involvement completely.  Obviously, that isn't politically possible, but it is the standard we should use to judge potential changes.  Decentralization moves us closer to freedom.  Greater freedom of association, which includes the power to reject outside students who may be disruptive, moves us closer to freedom.

Finally, Rep. McMillin asked for alternatives, which I'll assume means politically feasible alternatives.  First, expand the number of charter schools, and let them accept those Detroit students who actually want an education.  (Of course, they have to be free to reject those who don't.