“The DOJ, just to get at Steve Bannon, absolutely tore asunder a vital fundamental constitutional principle,” he determined. “As you know, we have separate branches of government. So when the president or former president — and we know that a former president has the right under the law to invoke privilege — when [a president] invokes privilege, that means that privilege is presumptively valid. It’s not for Congress to determine whether it’s valid, how broad it is, or otherwise.”