What is less important is how they lean, what is more important is who appointed them and who they have their loyalties to. Their voting record tells even more.
That doesn't mean anything. Loyalties can be bought in the United States. For example, although Anthony Kennedy was nominated to the SCOTUS by Reagan, he has increasingly sided with Ginsberg and the rest of the pro-LGBT brigade. Perhaps he thought that siding with the Liberals will give him better career prospects.
By the standards of your own argument this would clearly demonstrate who bought them by examining the pattern of their rulings, so in fact it does mean something.
