Political bias measured in Supreme Court Decisions

The NYTimes reports that how Supreme Court Justices vote on 1st Amendment claims depends on their political leanings. The worst liberal bias is 1.3, whereas the conservative biases range from 3 to 7.

This is unsettling enough by itself, but even more disturbing is the implication is that conservative justices may be more biased in other areas besides 1st Amendment issues.