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(CNN) President Donald Trump's impeachment lawyer Alan Dershowitz on Wednesday rolled out a novel and very Trumpian legal argument in his client's defense: The President's personal interest is the national interest when he's up for reelection.

The logic here is that Trump believes his reelection is what's best for the country, so therefore whatever he does to secure a second term is, by definition, in the national interest. That's despite the fact that what he did was hold up US aid, approved by Congress, as leverage to get the investigation he wanted into former Vice President Joe Biden, his potential 2020 rival.

Could any President be impeached under that standard? I talked on Wednesday's podcast with CNN legal analyst Michael Zeldin. Plus, CNN congressional reporter Lauren Fox describes the scene at the Capitol and whether former national security adviser John Bolton will be called as a witness. Listen here

Trump explodes at Bolton and wavering Republicans

Agitated, under pressure and still unsure he has enough loyalty among Senate Republicans to dictate when his own impeachment trial will end, Trump lashed out Wednesday at his former national security adviser as his White House tried to halt publication of an unflattering book that confirms elements of the storyline that got Trump impeached by Democrats.

Rage on Twitter targeting Bolton

The President personally attacked John Bolton, who was fired by tweet in September just before the Ukraine scandal erupted. Bolton is apparently willing to testify at the impeachment trial and, apparently, spill the beans on their private conversations he has detailed in a forthcoming book. Dismissing Bolton as someone who "begged" him for a job, Trump said, "if I listened to him, we would be in World War Six by now, and goes out and IMMEDIATELY writes a nasty & untrue book. All Classified National Security. Who would do this?"

Trump's millions of Twitter followers witnessed the President's frustrations, but his real audience was the handful of Republican senators who won't bend to his will and end his impeachment trial ASAP.

Bolton is already part of this trial

During the first day of Senate questions -- which were read, deadpan, by Chief Justice John Roberts -- Bolton played a big role.

The first question was posed by three Republican senators who've suggested they might be open to calling witnesses (Mitt Romney, Susan Collins and Lisa Murkowski).

The second question, posed by Minority Leader Chuck Schumer, was whether the Senate could return a "fully informed" verdict without testimony by Bolton and others.

Worth noting

The President's defense attorneys in his Senate impeachment trial have criticized the House impeachment managers for not producing any firsthand witnesses alleging that any quid pro quo came from the President himself.

Bolton got a formal threat, too

CNN's Jake Tapper reports The White House has issued a formal threat to Bolton to keep him from publishing his book, "The Room Where It Happened: A White House Memoir," sources familiar with the matter tell CNN.

In a letter to Bolton's lawyer, a top official at the National Security Council wrote the unpublished manuscript of Bolton's book "appears to contain significant amounts of classified information" and couldn't be published as written. The letter, which is dated January 23, said some of the information was classified at the "top secret" level, meaning it "reasonably could be expected to cause exceptionally grave harm to the national security." Read the letter here

What's in the book?

Reports from The New York Times and The Washington Post suggest that Bolton's book details a time last August when Trump directly linked $391 million in security aid to Ukraine with that country's government launching investigations into former Vice President Joe Biden and his son Hunter. Trump has repeatedly made unfounded and false claims about Joe Biden relating to Ukraine.

Also: Bolton called Democratic congressman in September

Democratic Rep. Eliot Engel, the chairman of the House Foreign Affairs Committee, said in a statement Wednesday that Bolton tipped him off way back in September -- just as the Ukraine story was breaking and before the impeachment inquiry -- to investigate the ouster of US Ambassador to the Ukraine Marie Yovanovitch. Story here

Democrats, get ready for the Hunter Biden debate

Play a little political chess in your head and you can envision a scenario where Democrats are the ones to ultimately kill the idea of hearing witnesses at the impeachment trial because they don't want to call Hunter Biden.

If it emerges there are four Republican votes to hear from John Bolton -- I am still extremely skeptical -- Republicans will insist that Democrats suffer witnesses too. The number one GOP request could be Hunter Biden, whose appearance would be uncomfortable for his dad, Joe, who is in the top tier of Democrats vying for the party's presidential nomination.

Should Roberts make the witness decision?

Both Collins and Romney have suggested both sides of the aisle should get witnesses. And now, even moderate Democrats like Sen. Joe Manchin of West Virginia are sounding open to the idea, although he'd like to defer the decision-making to Roberts, who is presiding over the whole trial.

"I want witnesses," Manchin told CNN. "I definitely want witnesses. The only thing I've said is that there should be an adult in the room and that's Chief Justice Roberts. We should vote again on Chief Justice Roberts being able to determine who is pertinent... if Hunter Biden is one of the people who is pertinent to the evidence or to the trial then absolutely."

In an interview Wednesday night on CNN's "Cuomo Prime Time," Manchin said he wants the process to be fair.

"What I meant to say was that I believe it has to be fair," Manchin said. "If the Democrats get 1, 2, 3, 4 -- shouldn't the Republicans get the same amount? But they should be relevant to the charges made against the President."

Democratic Sen. Tom Udall of New Mexico doesn't think Biden would have much to offer to the trial, but he told Bash he'd consider ceding authority to Roberts.

"I would be okay him making a decision on relevancy," Udall said. "It's a lot better than us fighting on these partisan things of this witness, that witness back and forth. Should there be a trade, all those kinds of things."

If McConnell really wanted Hunter Biden to testify, he'd already have been subpoenaed

Other Democrats are extremely opposed to Biden appearing. And Schumer pointed out Republicans actually have the votes to call Biden right now.

"Trump and McConnell could call for Hunter Biden today. They don't want to. They know it would turn things into a circus," Schumer said.

And bookmark this piece for after the witness debate is over: Red state Democrats won't rule out clearing Trump

Lamar!

"The Lamar Alexander question. That is the whole ball game," said Dana Bash on CNN after talking to senior Republicans about their effort to squash witnesses at the trial.

It's well known that Romney and Collins want to hear from Bolton. Murkowski is on the bubble. But Alexander could be the necessary fourth Republican vote for Bolton testimony.

Why Alexander would support witnesses:

1. He's an old school pol who respects the deliberative properties senators like to talk about in their institution.

2. He's retiring and not beholden to voters.

Why he won't:

1. He's not exactly a moderate, although he prizes bipartisanship.

2. He's very close to Senate Majority Leader Mitch McConnell.

Bash reports Senate Republicans find it hard to believe that Alexander in particular would break with the party. That's not saying he won't, but they think he is less likely to do it at the end of the day.

The bad precedent argument

The argument Alexander's colleagues are using with him, and others, is that if the Senate agrees to "do the House's work for them" it would set a precedent such that the House -- which can pass anything with a majority -- can keep doing this with impeachment in the future, jamming the Senate and taking the body off course from its agenda.

Lead impeachment manager Rep. Adam Schiff hit back at this idea during question time at the trial Wednesday.

"Think about the precedent you will set if you don't hear witnesses," he said.

Extra credit: Known for his walking campaigns across Tennessee as a Senate candidate and across early primary states as a presidential candidate, here's Alexander on C-Span when he walked across New Hampshire in 1995, wearing his red checkered lumberjack shirt. His signature campaign signs said, "Lamar!"

More from the proceedings

The Barr question -- Bolton's book could draw Attorney General William Barr into -- Bolton's book could draw Attorney General William Barr into the impeachment political fight that Barr has deftly avoided for months , write CNN's Evan Perez and David Shortell. Private conversations between Bolton and Barr, who have known each other for decades, are featured in Bolton's draft manuscript for his book, appearing to lend credibility to some of Bolton's sharpest critiques of the President who fired him.

Separately, given the role Barr played in Trump's call with Ukrainian President Volodymyr Zelensky, it's remarkable to me that Barr has not been drawn more into the impeachment fight.

The John Roberts court -- Roberts' role in all of this is not unlike a clerk of sorts. His challenge today is -- Roberts' role in all of this is not unlike a clerk of sorts. His challenge today is reading the questions senators have written out . He played it straight. Like the umpire he promised to be!

Dershowitz v. Warren on the law -- Dershowitz, s former Harvard law school professor, says Massachusetts Sen. Elizabeth Warren, a former Harvard law school professor, doesn't understand the law after she -- Dershowitz, s former Harvard law school professor, says Massachusetts Sen. Elizabeth Warren, a former Harvard law school professor, doesn't understand the law after she criticized his defense of Trump at the impeachment trial