As far as I'm aware, the same company, Hat Trick, is making the US version as has long produced the UK version. I suspect a bunch of the British team has been in the US putting this together - at least initially.
The UK version is taped 24 hours ahead of broadcast, and usually tapes for 2-3 hours to make a 27 minute ad-free version for the BBC. A slightly longer edit at 42 mins or so is available (and plays later on Dave&U in a commercial hour). So I'd be amazed if the US show was live. It's one of those panel shows where the scores don't matter and you simply drops rounds/gags that don't work by massively over-recording and then producing something a bit tighter.
Obviously, key to panel shows on the BBC is that they are commercial free and 30 minutes (or 27 mins in reality) is tight enough to leave you wanting more. I'm mostly not a fan of stretching shows out to a commercial hour like this, and think it shows why these formats of programmes work in the UK and don't in the US - at least to date.
To be clear, the UK show is now formatted with a weekly guest host (often the same guests working once a series), two regular team captains and then a mix of comedians, politicians (if they're game), newspaper pundits, TV presenters and others. They obviously need to have a grasp of current affairs, and yes, it's tough to get a word in amongst three other comedians. Ian Hislop, on the UK captains, isn't a comedian as such - he edits the satirical magazine, Private Eye. But he's been doing this show long enough that he can quip quickly. But they allow space for the non-comic guests to come in. That said, you get weeks where the non-comic seems to say very little and you guess that the editor has earned their money finding even a few seconds of footage to show that they said anything in the recording session!
I don't think they're showing this on the international version of CNN we get here. But I'll keep an eye out. These shows always take time to bed in, although I'm sure they've made one or two non-broadcast episodes before going live.
Adam