Mr. Yglesias points out that every time there is a Supreme Court vacancy he argues against lifetime appointments. I usually ignore him but it is time to point out that I profoundly disagree.
He argues about alternative strategies, term lengths, and the like but outside of pointing to age and other minor flaws, fails to provide a solid, cogent argument favoring the change. He ultimately says "fixed-term system would create a predictable relationship between winning presidential elections and appointing justices, and it could also contain a sensible process for replacing a sick or dead justice." That doesn't seem like much of a reason to create such a profound change.
Let me address what I think are minor points first. He argues that there is "undue weight on throwing up young appointees." I think that there is a lot of value in having appointees of all ages. "Throwing up" young appointees on a court with a system of lifetime appointment helps create a mix of ages on the court. It think it is a positive rather than negative thing.
I don't share his concern about the current system generating a lot of randomness. Life is filled with randomness. Our political system is filled with randomness. Efforts to control that will, of necessity, fail. Meteors fall into buildings. Young people die.
As for the current model, I think that people grow in the job. They learn. Then gradually change their perspectives. They apply law to new people and situations. They learn to work with one another in spite of themselves. Over time they don't always end up like they started. And some of that means that they become more wise. A look at the career of Earl Warren will give you an idea of what I mean. This wouldn't happen with a finite appointment.
The fixed-term model that Mr. Yglesias proposes -- a single non-renewable term -- is already in place for the Comptroller General who has a single 15 year term and retires at full salary. However it doesn't remove the political or financial considerations. In fact it may amplify them. The most recent Comptroller General removed himself after about a decade to take a position as President of the Peter G. Peterson Foundation. They were able to trade on his previous job title. And all of the contacts made during his term provided him with a fine rolodex. In other words that fixed-term model just provides a foundation for a more powerful lobbyist.
Think of a lifetime court appointment as tenure. As the formation of a group of knowledgeable people we hope will become wise. Folks who can learn to base their personal self-worth on their ability to be fair, to work for everyone, to maintain integrity. That isn't worth giving up.