It is a horribly biased article... My favorite trick libs use is to call the four libs on the Supreme Court "moderates" and the other five conservatives.
The only interesting part of this article is the first ten or so pages that delve into the back dealing of the SCOTUS during Bush v. Gore... Seems like they only interviewed law clerks for the liberal Justices, so who knows if ANY of it is accurate, but it IS a rare look behind the scenes of the Court, which for a lawyer is somewhat interesting.
Problem is, his attitude was that clerks were controlling the justices, influencing them in different ways, etc., like puppets on a string.
Of course, when you look at the legal rulings of an SC justice over many years, you realize that individual law clerks (who change each year) could not have been influencing them too much, since the justice's attitudes towards a subject stayed pretty much the same year after year (see for example Thomas on property law).