A loyal reader asks that I write about tenure. So some thoughts:
First, tenure is constantly evolving. The system that we have in the United States, created with the notion of protecting academic freedom, has become multi-threaded: the version at many academic medical centers (at large research universities with a medical school) has less to do with guaranteed salary and more to do with faculty prestige and rank. The version at large public research universities without medical schools is often backed by the tuition of students and carries with it, an implied teaching load with the potential for “course buy-downs” from research grants (although almost never to zero). At liberal arts colleges we find that tenure often brings the promise of salary growth (albeit slow and often non-meritocratic), substantial course loads and an explicit obligation to play a personal role in undergraduate education above and beyond the classroom.
Tenure in some countries in Western Europe resides nationally and can involve being assigned to a university in a potentially inconvenient town or city.
Finally tenure in some places is being rolled back to things like rolling 5 year contracts, with the general expectation of renewal, but no guarantee.
But the function of tenure, from my viewpoint, is now much more connected to the ability of institutions to retain talent and reward merit, than the original intent of protecting academic freedom–at least here in the States. That is not to say that tenure isn’t still invoked to protect the free expression of scholarship in the academy–it’s simply to recognize the reality that those occasions are quite rare.
One of the most interesting aspects of tenure is that it seems to be transferable within academia. This isn’t explicit, but by and large, having earned tenure at one institution of higher education, subsequent employment at a new school usually carries the old tenure decision forward (perhaps with promotion). This is both an aspect of a competitive market (it would be difficult to recruit a tenured faculty member without the promise of keeping their tenure at the new place) and the notion of tenure as an earned academic badge of merit (as for example the doctoral degree is also a badge).
By and large, I think tenure is a good thing. It allows an institute like Krasnow–which is able to grant tenure within George Mason University–to have a competitive edge against elite stand-alone centers which may not. But it is essential to keep in mind that tenure is not a license to dial back and become the proverbial dead wood.