Giving up on the Constitution?

For many years now I've been teaching my students that a constitution is more than a scrap of paper but is to be found in the deeper principles and commitments of a particular political community. Here in Canada in recent decades we have embraced the notion that our constitution is identical to our codified Constitution Acts, while traditionally we have recognized other sources of our constitution, including organic statues (i.e., ordinary laws whose subject matter is constitutional), court rulings (including those of London's Judicial Committee of the Privy Council prior to 1949), and, above all, the unwritten conventions of the constitution, such as responsible government.

Superficially, Louis Michael Seidman would appear to agree with this understanding of a constitution, desiring to import it into his American context:

Countries like Britain and New Zealand have systems of parliamentary supremacy and no written constitution, but are held together by longstanding traditions, accepted modes of procedure and engaged citizens. We, too, could draw on these resources.

However, Seidman goes much further: Let’s Give Up on the Constitution. Why? Because it's been ignored numerous times in the past and, as an 18th-century document, it is no longer suited to the 21st-century United States.

What has preserved our political stability is not a poetic piece of parchment, but entrenched institutions and habits of thought and, most important, the sense that we are one nation and must work out our differences. No one can predict in detail what our system of government would look like if we freed ourselves from the shackles of constitutional obligation, and I harbor no illusions that any of this will happen soon. But even if we can’t kick our constitutional-law addiction, we can soften the habit.

Yet what if it turns out that the most central of these "entrenched institutions and habits of thought" is the respect that Americans hold for the very document he wishes to abandon? No one is asking Seidman or anyone else to believe that its origin is divine, but one would be foolish to give up on something as crucial as the general reverence for the rule of law, which can hardly be taken for granted in much of the world outside of the west. Seidman is, of course, welcome to work for changing the law, but it seems incomprehensible that a constitutional law professor would be so ready to relinquish, not just an old document, but that intangible and durable consensus undergirding its status — and indeed his own profession.