Judges in the common law tradition are also obliged to apply the law as written (whether they like it or not). The expression 'interpret the law', when referring to a judge's duties still holds its original legal meaning and intent of simply reading the law as written. This sense of the word 'interpret' came from a time when literacy was rare, and reading was seen as 'interpreting' mysterious symbols on a parchment. Judges do have legitimate leeway to 'interpret' in the modern sense when it is not clear how the written law applies to a given case, but even then they are expected to do this in good faith: they are expected to make the old law apply to the new situation, not to make new laws (i.e. judicial activism), which is outside of their remit.
