Clarence Thomas has always been more conservative than Scalia, and in the past three sessions, so has Samuel Alito.
- Click here for the article.
Other commentators argue that Scalia's conservative scores were compromised by his support of limits on unreasonable search and seizures. Neither Thomas not Alito seem that concerned about it. I have no idea what changed in 2000 to send Scalia in a more liberal direction. 538 argues that justices tend to get more liberal as they get older. Maybe that has something to do with it.
For a closer look at the scores used to measure ideology among Supreme Court justices, click here.