If you were on Twitter on Thursday, you probably saw NBC News get mercilessly pummeled for this article, but more so for this tweet, which summarized the article by saying that the first day of impeachment hearings “lacked the pizzazz necessary to capture public attention.”

The criticism was appropriate — we’re talking about abuse of power and violations of the president’s responsibilities, and there are more important things to worry about than whether the proceedings feature sufficient pizzazz.

But you know who would bring pizzazz to this proceeding? And who is also a vital fact witness who needs to explain what he and the president were up to in Ukraine?

Rudolph W. Giuliani, that’s who. Get him in the witness chair, and we’ll have some serious pizzazz.

Democrats issued the Trump lawyer a subpoena for documents and records, which he said he’d refuse to comply with because breaking the law has apparently become something of a habit. Democrats could subpoena Giuliani directly, and if he refuses, which he would, they might consider taking him to court.

After all, he is at the absolute center of the Ukraine scandal. He was charged by President Trump with pressuring Ukraine to open an investigation that would hurt Democratic presidential candidate and former vice president Joe Biden, something Giuliani hasn’t been shy about admitting. Along with his goons Lev Parnas and Igor Fruman (who have since been arrested), he engineered the firing of Marie Yovanovitch, who will be testifying on Friday, as the ambassador to Ukraine.

One witness after another has testified that they were forced to coordinate Ukraine policy with Giuliani despite him having no official role in government. Again and again, Trump told people that when it came to implementing his wishes on Ukraine, they had to talk to Rudy.

Or, as Giuliani said back in May, “We’re not meddling in an election, we’re meddling in an investigation, which we have a right to do,” adding, “There’s nothing illegal about it. Somebody could say it’s improper.”

It’s that kind of candor that would make Giuliani both entertaining and revealing as a witness. He’d also be the most important fact witness in the whole inquiry, other than the president himself (who obviously won’t be testifying).

There are a thousand questions one might ask Giuliani, and on Wednesday we got a hint of something else that needs to be explored.

William B. Taylor, the acting U.S. ambassador to Ukraine, revealed that one of his staff was present when Gordon Sondland, the U.S. ambassador to the European Union, called the president from a restaurant in Kyiv, and the staffer overheard Trump expressing strong interest in the progress of the project to get Ukraine to investigate Biden and his son Hunter.

Now, we’re learning from the Associated Press that a second embassy staffer overheard the call as well.

As many people have pointed out, speaking to the president on an unsecured cellphone is a shocking violation of security protocols, and the chances the Russians were listening in are somewhere around 100 percent.

So how many such conversations has Giuliani had with the president on his phone? How much intelligence has he unwittingly provided to foreign adversaries in this fashion?

I suspect it’s quite a bit. Giuliani, the former New York mayor who somehow manages to market himself as a cybersecurity “expert,” once locked himself out of his iPhone, and regularly butt-dials reporters.

If Trump’s efforts in regard to Ukraine were as unimpeachable as he claims, Republicans would be eager to have Giuliani testify to clear all this up. But, of course, they aren’t. And you might assume that Giuliani would refuse to testify, but there’s a problem there, too.

Although Giuliani calls himself Trump’s “personal lawyer,” it’s unclear whether he provides any actual legal services to the president. He certainly can’t claim attorney-client privilege to protect his activities with regard to Ukraine, since that privilege only covers legal advice a lawyer gives to a client. Trying to get a foreign government to investigate a potential 2020 rival doesn’t qualify as giving legal advice.

Nor can Giuliani claim executive privilege. It’s questionable whether executive privilege can be applied to anyone who doesn’t actually work for the government, but even if it could, Giuliani was representing Trump in his private capacity, not in his official capacity as president.

Which leaves Giuliani one option for keeping his mouth shut: the Fifth Amendment. He can, of course, exercise his constitutional right to refuse to answer questions lest he incriminate himself, which his lawyers would probably advise him to do. But Democrats should give him that chance. If he simply refuses, they should immediately file suit.

I’d also like to hear Republicans explain why they think Giuliani shouldn’t testify, given that we can all agree that no one was more deeply involved in this scandal than him. Can’t he clear all this up?

That brings up another question: Do the Republicans have any exculpatory witnesses they’d like to call? Sure, they want Hunter Biden to testify so they can yell at him about bizarre conspiracy theories. But he has no information to offer about Trump. Do the Republicans have any fact witnesses who could explain why Trump is innocent?

If they do, they haven’t revealed them yet. But there’s no one who needs to answer questions more than Giuliani. So let’s get him in the witness chair.

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