Three new constitutional amendments

The Cato blogad at the right, and Jim Buchanan’s new essay, ask what three amendments you would pick for the American Constitution.  Will Wilkinson suggests an amendment to ban interference with voluntary exchange.

Sadly, I am unable to come up with good candidates.  I have plenty of ideas, such an amendment to forbid tariffs and quotas on foreign goods and services (would it cover health and safety concerns?  Would we be assured of non-pasteurized French  cheeses?).  But I worry the amendments would place too much weight on the Constitution.  It is easy to ignore a Constitution or to overturn it altogether.

Libertarians (and contractarians) often treat the Constitution as a kind of free variable to be manipulated.  We can write into it what we want, and if we fail we treat this as a kind of lament, or a sign of moral decay, rather than a problem with our basic approach.  In my view, if a constitution deviates from popular opinion (or is it the prevailing structure of interest groups?) by any more than "k" percent, that constitution will be chucked.  Furthermore changing your constitution too much, or ignoring it too blatantly, is costly in terms of long-run political order.  I view this as a constraint to be satisfied by political thinking, even though we can (and should) criticize that constraint at a meta-level.

That is why my three amendments would have to be modest.  Free trade might stick as an amendment, especially if we added a national security clause.  The Finns didn’t get very far with a supermajority requirement for fiscal policy.  I don’t see "procedural" approaches, such as term limits, as yielding much gain.  But local municipalities should not be allowed very strict anti-barbecue codes; I don’t care what they do with the smoke.  Nor should commuters be forbidden from driving on side roads during rush hour, just because the homeowners don’t like it.

Here is one relevant critique of Buchanan.  Surely you all have better ideas for three constitutional amendments; comments are open.