Should all laws sunset?

A recent article on Germany's system of periodic legal review got me thinking. Specially-tasked panels in the government review old laws and recommend updates to the legislature; some old laws are recommended for repeal. There is an obvious efficiency advantage to updating old laws, but there is also a democratic value to it as well. Why do laws bind future generations indefinitely? The problem is even worse when you consider laws passed by slim majorities. As a thought experiment, I like to ask my students to consider this proposition: All laws should sunset.

Here is the scenario I give them: the size of the majority that passes the law will determine its longevity. I give them this function as an example: years duration = 0.0005 x^2 + 0.0012 x + 1, where x is the margin of victory minus 1 (the coefficients are scaled to the U.S. House of Representatives). A one-vote margin of victory would entail a year's duration. A more standard party-line vote, say 242-193, would result in a two-year duration. Around a 60% majority, say 255-180, would result in a four-year duration. A unanimous passage would result in a 96-year duration. This example seems reasonable, so it forms the basis for our discussion.

Three interesting game theory questions always come up.

1. This gives a meaningful distinction to a vote to abstain, from a yes or no vote. The vote to abstain does not impede the law's passage, but it does limit its duration.
2. This gives the ruling party in Congress a real incentive to craft bipartisan legislation, if they want the law to endure beyond one term of the House. This could backfire, of course, and make the country even more difficult to govern. Not least of the reasons why it might backfire is the notion that Congress will have a very full docket re-passing about-to-expire laws. The tax code comes to mind as a frequently recurring matter, because it will never pass with large majorities.
3. What about repealing laws? Say a law has 76 years left. Does Congress have to muster a supermajority (411-24) to repeal it (an all-or-nothing repeal rule)? Or would the repeal rule be that a simple majority could "injunction" it for a year, but then the law would come back in force? For the purposes of the discussion, I usually go with the latter idea -- it more cleanly hews to the idea that laws should not be binding in perpetuity.

Students have a fun time discussing this idea. Invariably, we discuss how difficult it might be for everyone to comply (the lack of predictability), but I try to steer the discussion to this core idea at the heart of the thought experiment: Ought some rights exist in perpetuity? Is it democratic to have a fixed Bill of Rights?

Here's some further reading. And another article on the liberal bias to policymaking, specifically because it is difficult to repeal laws.