My favorite example of this is in Citizens United, where the Government's attorney, in response to a question from Justice Alito, conceded that the Government's interpretation of the First Amendment would allow it to ban political books close to an election. See pp. 26-27: https://www.supremecourt.gov/oral_arguments/argument_transcr...
Was the relevance simply the admission that the government didn't have an answer to the criticism?
I don’t recall the details, but I’m sure it came up in the opposition’s briefs. But in a brief you can paper over a thin argument to an extent. You can accuse the opposition of invoking a slippery slope, spend a lot of words making subtle distinctions, etc. It’s certainly fair to say that parties’ briefs often overstate the gravity of the consequences one way or another. So upon reading the briefs, the response might seem quite plausible. But when you’re forced to give a succinct answer to a direct question at oral argument, that kind of evasion falls apart and you’re forced to fully own the implications of your position.
I thought usually the surprise is how conservative, arrogant, and/or ideologically driven [vs consistency or actual principles] he is. Which seems to mean more conservative and extreme takes than expected vs any surprise votes that don’t swing that way.
Like his takes on the power a former president he loves can or should have. Including vs the current president.
That said, love the oral arguments and have probably listed to and read more than a hundred. They are usually pretty easy to fallow and far more balanced and informative the media summaries