I don’t know about $5m per year, but based on the importance of the job, a high six-figure salary makes sense. But, yeah, that has to be paired with a contract / oath that locks them down much more than an ordinary person. Instead of getting a free pass to do insider trading, any insider trading is punished harshly. Instead of a revolving door between congress and lobbying, require at least 5 years between leaving congress and doing any kind of lobbying work.

It should be the same sort of deal with being a supreme court justice. It should be a job where you never have money worries. But, also one where you’re forbidden from getting any other income or substantial gifts. If you want to be a motivational speaker as a justice, great, but you can’t make a cent doing that. If you want to write a book, wonderful, but as a justice anything you write (even on your own time) immediately goes into the public domain.