Hey, everyone. I'm David Chalien, the CNN political director. This is the Daily D.C. impeachment watch.

Every weeknight, we bring you the very latest reporting and analysis related to this historic impeachment saga.

We thought today was going to be a relatively slow day on the impeachment beat as the

conflict with Iran has dominated the news cycle, but boy, were we wrong. Earlier today, former

national security adviser John Bolton announced that he is willing to testify at the Senate

trial if he is subpoenaed to do so. This came completely out of the blue today, and it has major implications,

so there is a lot to unpack. In a few minutes, I'll be talking with Alice Stewart, a Republican

strategist, and a CNN political commentator. But first, I'm joined by my colleague CNN senior writer

Zach Wolf. As many of you know, Zach publishes the impeachment watch newsletter, which you can subscribe to at CNN.com slash impeachment.

Zach, thanks for joining me.

Thanks for having me.

So, Zach, we get this statement today from John Bolton.

Nobody was expecting it.

There was no indication it was coming.

As you know, whether or not John Bolton could testify in the House was a matter for the courts

until recently, and there was no adjudication there. But it now seems he's raising his hand

to say, hey, I am available to testify in the Senate trial. We did hear his name invoked

many times throughout the House proceeding.

So from a 30,000 foot view, tell us how crucial a witness John Bolton could be in this entire impeachment trial of Donald Trump.

John Bolton is, I think, perhaps the most important person we haven't heard from in terms of what exactly was going on in the White

House with the National Security Council at the time in August and July with all of these things.

He wasn't on the call, we don't think, with President Trump and Vladimir Zelensky.

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