The current salary for a justice is $298,500 (the chief justice makes an extra $11,000 a year for his additional duties). That compares with $257,900 for federal appellate court judges and $243,300 for federal district court judges. Sounds good right? But average profits per equity partner at the top 19 law firms in New York range from $2.4 million a year to over $8 million. The head of a Supreme Court practice, as someone like John Roberts would be, will typically make a good deal more than the average equity partner at his firm.

Now, consider what kind of money Roberts could make as a former Chief Justice. ...

But if the justices go in knowing they can serve 18 years and may well be leaving the bench before they are ready for retirement, the whole incentive structure changes.