Isn’t it considered a “corrupt bargain” to offer specific appointments in exchange for political support? Sure quids pro quo happen with a wink and a nudge in private, but not as a public statement. Granted, Biden just answered a question out of the blue, but a candidate free of stupidity and hubris would have said, “that’s an interesting thought; Obama would make a fine SC justice” or some such drivel.
You make a great point, he should have answered with more tact as you suggested.