So if you're interviewing a person you know just lies out of habit, probably not even trying to lie (although maybe so - I suppose that's a possible strategy to lie so much people don't know when you're doing it on purpose), and lying in a particular context is a felony, isn't that entrapment?
I mean, not that I'm pleased by our sitting president, but that sounds like people are just "we're trying to get him out of office no matter what, even if it's just on a technicality." Just feels... not good all around.
It's a risk, yeah. However, Trump has done depositions before (remember, he's been involved in ligitative stuff most of his adult life), so, he knows how to handle that stuff. Plus Mueller is a professional and he acutely knows what's on the line.
Mueller doing a Trump interview this soon (could still be many months away) seems a bit surprising since interviewing Trump would actually be near the end of the investigation. So, I'm not sure if it was initiated by Trump or initiated by Mueller.
Also, amid rumors that Oprah Winfrey is thinking of doing a 2020 run, the WH basically said "Bring it on.". Okay, they actually said "We welcome the challenge.", but that's the same message.
That's not what entrapment is. Leaving an expensive convertible on the street with the keys in the ignition waiting to jump on some sucker that gets in, that's not entrapment. Having an undercover cop walk up to someone nearby and be like, "hey, want to steal that car? No? What are you, a bitch?" That would probably be entrapment. Tempting people isn't entrapment, coercing them is.
So unless Mueller or an associate directly makes an appeal to Trump to lie, they aren't entrapping him. Simply giving him the opportunity to lie is temptation not coercion.
Additionally, poor character is not a legal defense. Else kleptomaniacs and convicted thieves would have some weird arguments at their disposal. "But officer, they put all those expensive jewels right out where anyone could take them! It wasn't even reinforced glass!" If Mueller or someone else in the proceedings were to use as evidence Trump's past lies, that would be an argument *against* Trump not for him.
Its all moot regardless. US law runs on precedent and that's how they got Bill Clinton.
The court of public opinion isn't neccesarily going to make that distinction. If conservative outlets sense evn a slight hint of percieved entrapment, then they will make that claim.
Mueller and his team are top rate professionals, they'll be careful in what they do.