Jeffrey A. Segal and Albert D. Cover developed the Segal-Cover scores that are widely used to proxy the political ideology of Supreme Court nominees. Segal-Cover scores are described here (gated) and here (ungated). The scores are based on the coding of newspaper editorials, with each paragraph in the editorial coded as liberal, conservative, moderate, or not applicable (p. 559).
Segal and Cover helpfully provided examples of passages that would cause a paragraph to be coded as liberal, conservative, or moderate. Here is Segal and Cover's first example of a passage that would cause a paragraph to be coded liberal:
Scarcely more defensible were the numerous questions about Judge Harlan's affiliation with the Atlantic Union. The country would have a sorry judiciary indeed, if appointees were to be barred for belonging to progressive and respectable organizations.
Here is Segal and Cover's first example of a passage that would cause a paragraph to be coded conservative:
Judge Carswell himself admits to some amazement now at what he said in that 1948 speech. He should, for his were the words of pure and simple racism.
I can't think of a better example of conservatism than that.