As this is (or would be) a hakhel year I was doing some reading up on Hakhel and came across the following statement in a chabad.org article:
If there is no king – as was the case in the hundreds of years until Saul was anointed –the leader of the generation reads.
I can't find a source for that anywhere, the chabad article doesn't cite it. Any idea where it's from? I've checked the obvious places - Rambam, Sefer HaChinuch, and a few relevant sugyas in the Talmud but I can't find it. Any idea where this halacha is from?
Just to clarify I realize there may be historical precedent from the story of Ezra, but I'm looking to see if/when this was actually codified into halacha.