Nancy should have the House Sergeant at Arms arrest Barr at his press conference and frog march...

And to suggest that she does, is irresponsible.

and considering he is AG and the more commonly (these days) contempt statute would be prosecuted through the DOJ... well, you see the problem with going the normal (these days) route.

That said, even exercising inherent contempt would not play out *exactly* in the manner the OP described. But the House *could* go through the contempt process, and the House Sergeant at Arms *would* therefore be able, legally speaking, to arrest/imprison Barr. And it is (apparently) unpardonably by the POTUS.

https://en.wikipedia.org/wiki/Contempt_of_Congress#Inherent_contempt

Whilst these powers have not been used in nearly a century, they do exist, and *could* be used. The question is whether the reward of doing so is worth the risk... and we've already seen a hesitancy to lay down markers on impeaching Trump, with the same question being the issue.

and let it fly on live tv at this contrived press conference. Just do it.

was used to justify firing Comey and Trump/Sessions redirected that blowback in his direction -- he was totally willing to write such a memo, he was totally willing to participate in firing Comey, he just didn't want to *take the blame* for Trump's decision.

He was able to rehab his own rep by appointing Mueller because Sessions had recused himself. But that ship has sailed. Now that Barr isn't recused, and Rosenstein got what he wanted by shifting responsibility for whatever happens off onto Mueller and Barr, Rod is back to being a disgusting GOP toady.