...there are probably no audio recordings of Trump et al admitting plainfully their coordination with Russians...

"If it's what you say I love it."

-Don Jr. in response to an email that was prefaced with, "as part of the Russian government's ONGOING EFFORT TO HELP YOUR FATHER..." And still no questions from the GOP members of the committee. How is an email record that different from tapes? The fact that Jr. didn't say, "If it's what you say, I love it, but wait, why if Russia trying to help my dad? That seems odd." is enough evidence that this wasn't an isolated incident. If that was the first he heard of Russia's effort to elect Trump and he didn't react, then he's literally the stupidest person in public life (since the language was so obviously inserted to use against him if necessary). The other explanation is that it was just routine at that point. Either way the evidence is pretty plain, so maybe even tapes of Trump saying things that even the tin foiliest hatted person in the world couldn't have dreamed up will never be enough.