In Deuteronomy 12:8, Moses tells the Israelites that once they enter into the land of Canaan and settle down, “you shall not do as we do here today – everyone what is right in their own eyes.”
The text goes on to explain that when in Israel, worship and offer sacrifices only in the one place where God will show them (i.e. the Holy Temple in Jerusalem).
In the book of Judges (17:6 and 21:25) the same phrase is used to describe a non-centralized political system with no king. Presumably here too it means the Israelites must shift from a non-centralized religious system to one centered around the Temple and the High Priest.
However, there is a problem with this interpretation. Aren’t the Israelites in the wilderness already living a centralized religious system? They march with the Mishkan literally in their center, and only there are they allowed to offer sacrifices, and Aaron (and subsequently his son Eliezer) presides as High Priest! The idea that everyone is doing what is right in their own eyes really does not seem to apply here the way it does in Judges, where the people truly do self-govern in a different way before the rise of kings.
Rashbam offers an explanation.
In every place where we encamp in the desert we offer sacrifices at the Mishkan, which is moved from one place to another. (Translation Martin Lockshin, adapted)
While not a perfect fit for explaining “what is right in your own eyes”, Rashbam emphasizes that the main difference isn’t about individual choice being restricted, but rather the mobility of the Mishkan.
Once the people are settled, their place of sacrifice should settle too. The shifting sites in the wilderness, which allow for the people to journey together with their place of worship, must be replaced by a central, stable Temple that will ground and unite the people as they spread out further away from each other than they were in the desert.
I remain dissatisfied by this explanation, mostly because I particularly like the phrase “what is right in your own eyes” as a phrase to live by. May our collective be cohesive, yet may we never be blinded to what is right, no matter how different it may be from those in power.
For more about Rashbam, see my introduction.