Well, those attributes at least made McReynolds a much better DEMOCRAT than Butler. ;-)
My example with Stephen J. Field fits the "exception to the rule" premise though. He was a Democrat justice appointed by a Republican president. I would say his voting record and judicial philosophy was comparable to Scalia and Butler, though the three of them came from radically different eras in U.S. history.
Yes, Field may be a better counterexample, but in the early-to-mid 1860s the Republican Party was less than a decade old and was still attracting a lot of longtime Democrats (Salmon Chase himself was an anti-slavery Democrat until 1857 or so),, so I don’t think of Field as a Democrat.