Why Do Supreme Court Justices Move to the Left?

The following quotation is taken from an interesting article on the judiciary generally, and on the tendency of Supreme Court justices to become more moderate and even left-leaning over time. It gives hope, but also implies reasons why the most recent appointees, like Scalia and Thomas, might remain as doctrinaire. This quote talks about a recent development that's affecting the independence of judges in the state courts, namely campaign contributions. Both unsurprising and scary:

"There is also recent evidence that state courts to which judges are elected rather than appointed have been powerfully transformed by campaign financing. A study by Texans for Public Justice, for example, found that the ten Texas Supreme Court justices elected or reelected between 1994 and 1998 raised over half of their $12.8 million in campaign money “from lawyers, law firms and litigants who filed appeals with the high court during this same period.” The study also found that, although the Texas Supreme Court declines to hear nearly 90 percent of the cases for which appeal petitions are filed, “the more money that a petitioner contributed to the justices, the more likely they were to accept a given petition.” For example, the court was ten times more likely to accept the petitions from petitioners who made campaign contributions of more than $250,000 than they were of those of non-contributing petitioners. Trends in decisions have also shifted over the same time period decidedly in favor of corporate defendants, and it seems likely that a major factor in that drift is the lack of the same independence-bolstering structures enjoyed by judges in the federal system."

--From "The Drifters: why the Supreme Court makes justices more liberal," by Jon D. Hanson and Adam Benforado. In The Boston Review, January/February 2006.