Lexington makes the case. He follows up at his blog:
Professor Klarman made four main points about what he calls "constitutional idolatry". They are (1) that the framers' constitution represented values that Americans should abhor or at least reject today; (2) that there are parts of the constitution America is stuck with but that are impossible to defend based on contemporary values; (3) that for the most part the Constitution is irrelevant to the current political design of the nation; and (4) that the rights that are protected today are mostly a result of the evolution of political attitudes, not of courts using the Constitution to uphold them.
Point (1) is surely unarguable: the protection of slavery, the restriction of suffrage and so on. Point (2): two senators per state regardless of population, restricting the presidency of a nation of immigrants to those born in America; (3) beyond Congress, the courts and the executive branch today's political system includes a fourth branch, the administrative state, which the framers could never have imagined and which is almost certainly "unconstitutional" in many ways but which no court will ever strike down; (4) when the Supreme Court has ruled to uphold rights it has generally been motivated by changing public opinion, not by a textual study of the Constitution. Judges, Mr Klarman says, are too much a part of contemporary culture to take positions contrary to dominant public opinion, no matter what the Constitution says.