Ramesh, it seems to me that the Equal Protection Clause is one of many examples of a constitutional provision whose precise meaning is probably indeterminate on an originalist analysis. If true, this raises interesting questions concerning what judges should do about it. But I do think there are good-faith originalist arguments that the EPC commands colorblindness, and I don’t take it that your excerpt is meant to be a full-scale rebuttal of any of those originalist arguments, including McConnell’s.
You’re right that no majority of the Supreme Court has explicitly said that the Constitution is color-blind, but that’s because of the way the Supreme Court analyzes constitutional claims. The Court doesn’t operate by declaring that constitutionally suspect government actions (i.e., censorship or racial discrimination) are absolutely impermissible; it simply specifies the level of scrutiny that those types of government actions must satisfy in order to be legitimate. Several different majorities of the Supreme Court have held that the Fourteenth Amendment requires the highest level of judicial scrutiny for any racial discriminatory by the government. In legal jargon, the discriminatory action must be narrowly tailored to serve a compelling government interest. This is the same level of scrutiny that applies to the censorship of political books. As far as the analytical framework for modern judicial review goes, this is the most colorblind the Constitution can get. For a long time, the saying was that strict-scrutiny analysis is “strict in theory, fatal in fact.” Certainly, this level of stringency forecloses segregation as a matter of constitutional law.
There has been some recent play in the joints of modern Equal Protection analysis in the context of affirmative action, but that has been based on the Court’s incredible finding that the superficial goal of race-based diversity is a compelling state interest, and that taking race into account is the most narrowly tailored way that colleges and universities could possibly make their classes more diverse. As a doctrinal matter, however, this does not suggest that racial discrimination is any less constitutionally problematic than trampling on political speech or violating any other fundamental constitutional right; it simply reflects the (poor) judgment of Justice O’Connor that racial diversity in university admissions is such a compelling goal as to justify racial discrimination in spite of its suspect status.