(CNN)Here are the key things to watch at President Donald Trump's Senate impeachment trial.
Things will change -- We have a basic outline of how we think the trial will go, but it's clear things will change as the trial progresses. For instance, much or all of Tuesday could be taken up by debate between the House managers and the defense team over how the trial will progress. Democrats are expected to seek to force a vote on including witnesses (more on that below) even before the opening arguments take place. According to aides to Senate Majority Leader Mitch McConnell, those opening arguments are now expected to begin on Wednesday afternoon.
Late nights -- There is a clear desire by Senate Majority Leader Mitch McConnell to get this thing done. He has broken with the precedent of the Bill Clinton impeachment trial, according to a draft of rules senators could vote on Tuesday. Instead of allotting four days each to the House impeachment managers and Trump's defense team for opening arguments, McConnell would give each side only two days to make its case. Since each side gets 24 hours, this first week in particular could go very late if the impeachment managers or Trump's team use all of that time, perhaps until 1 a.m. ET, or even later with breaks. The proceedings will get underway at 1 p.m. ET and run Monday through Saturday.
Relative speediness -- This also means the trial could go very quickly. Trump wants it wrapped up before he delivers the State of the Union address February 4. That would be a very fast trial, considering Trump's officially began Thursday. Clinton's lasted more than a month -- from January 7, 1999, until February 12. Andrew Johnson's trial lasted from March 5, 1868, until well into May, more than two months. But if the Senate doesn't agree to call any witnesses or subpoena any documents, Trump could be acquitted by the middle of next week.
RELATED: Impeachment guide: Voting on the trial rules
RELATED: Impeachment guide: Voting on the trial rules
A fight over witnesses -- Democrats want witnesses at this impeachment trial. Most Republicans do not. New information has come to light in the month since Trump was impeached. How much of that is presented at the trial is a very open question. And whether Democrats get to hear from witnesses like former national security adviser John Bolton is a very open question. We know there will be votes over witnesses. The question is whether the four Republicans needed to give Democrats a majority will agree to hear new information. That's a question likely to be answered later in the process, perhaps next week.
Parliamentary squabbling -- We have some idea what to expect, but the rules have not been set. The rules of the trial have not been released by McConnell nor have they seen a vote. The details of those rules, and whether McConnell can get a majority of 51 senators on board with them, will be very important.
Murkiness -- CNN hired former Senate parliamentarian Alan Frumin to help decode the impeachment trial. Asked if, under the rules, Democrats can force the Senate to hear witnesses, he said, "Like so much about Senate procedure the answer is a little murky. Senate procedure is murky generally and Senate procedure with respect to impeachment trials is murky squared." Read more about the rules.
Tight media control -- Reporters on Capitol Hill have complained that portions of the building normally open to them have been shut. In particular, senators will be able to walk around the second floor of the building without having to answer any questions from the media. That's a break from the long-standing tradition of Capitol Hill. In addition, the Senate controls cameras inside the chamber, so it will be able to control the angles seen during the trial. Only the person talking will be pictured, for instance.
Closed sessions -- When I ran the above items by Jeremy Herb from our Hill team, he added the important note that we won't actually see everything that happens in this trial. There's expected to be at least one closed session on Tuesday and possibly more, which will feel very strange, but is needed, according to Senate leaders, because senators aren't allowed to speak during the trial (among other rules like not using their phones and standing when they vote) and they'll have to debate at times about how to proceed. But we won't know the deliberations going on as a result.
This should be a bigger deal -- NSA and CIA accused of possibly withholding evidence
This allegation from House Intelligence Chairman Adam Schiff is quite troubling and should perhaps be getting more attention.
He's essentially accused the US intelligence agencies of being cowed by Trump into holding on to facts for political reasons.
"The NSA, in particular, is withholding what are potentially relevant documents to our oversight responsibilities on Ukraine, but also withholding documents potentially relevant that the senators might want to see during the trial," Schiff said Sunday on ABC News.
The California Democrat added: "There are signs that the CIA may be on the same tragic course. We are counting on the intelligence community not only to speak truth to power, but to resist pressure from the administration to withhold information from Congress because the administration fears that they incriminate them."
Amanda Schoch, the assistant director of National Intelligence for Strategic Communications, said in response to Schiff's remarks, "The Intelligence Community is committed to providing Congress with the information and intelligence it needs to carry out its critical oversight role. The IC is working in good faith with (the House Permanent Select Committee on Intelligence) to respond to requests on a broad range of topics and will continue to do so."
The arguments that will be made
We've already seen some indication of the arguments that will be made during the trial. House Democratic impeachment managers capped their months-long investigation with a brief for the Senate. They ceded that Bolton should be called as a witness and they mentioned, just once, the new information released by Rudy Giuliani's business associate, Soviet-born businessman Lev Parnas.
They'll leave further arguments over new information for the trial, apparently.
But Trump tried to block cooperation with the impeachment inquiry and has kept all documents he possibly could from lawmakers. So what's new in the filings his team presented in advance of the trial is an actual defense. They argued he was right to talk to the Ukrainian President about US elections in part because he, Trump, was trying to protect them.
Westwood and Pamela Brown profiled Pat Cipollone, the White House counsel who is about to become a household name as he defends his boss. Trump has described him as the "strong, silent type."
There was a crime, according to GAO
Much of Trump's defense has relied on the idea that no crime was committed in his conduct regarding Ukraine. But the Government Accountability Office, Congress' nonpartisan investigative arm, has determined that withholding the security aid from Ukraine violated the law. When asked about the GAO report that the Trump administration broke the law in withholding aid to Ukraine, sources working with Trump's legal team said it would not "get into something that is not in the articles of impeachment, except to point out that it's not in the articles of impeachment."
New CNN poll: Half support removing Trump
From CNN's polling director Jennifer Agiesta: About half of Americans say the Senate should vote to convict Trump and remove him from office in the impeachment trial (51%), according to a new CNN poll conducted by SSRS, while 45% say the Senate should vote against conviction and removal.
Clear majority favors witnesses
Nearly 7 in 10 (69%) say the trial should feature testimony from new witnesses who did not testify in the House impeachment inquiry. And as Democrats in the Senate seek to persuade at least four Republican senators to join them on votes over allowing witnesses in the trial, the Republican rank and file are divided on the question: 48% say they want new witnesses, while 44% say they do not.
Note from me -- 51% is not a supermajority
It takes a supermajority in the Senate to remove a president, and half of Americans do not equal anything close to 67 senators. But the number of Republicans favoring witnesses is really interesting and important, and makes clear that the GOP is not the monolithic pro-Trump being he says it is.
The poll is the first major national telephone survey since the articles of impeachment were sent to the Senate, formally launching Trump's trial there. They are also the first such poll results since Parnas publicly implicated the President in the Ukrainian pressure campaign during a series of television interviews.
Trump's approval rating is at 43% in the poll
That's a low in polling for a president in January of an election year. Gerald Ford and Bill Clinton polled at 46% approval in the January before they faced voters. Ford lost after Richard Nixon had resigned rather than be impeached. Clinton won reelection, but that was before his impeachment. After Clinton was impeached, his party lost the White House.
Bloomberg is no fan of impeachment
The late self-financed entrant to the Democratic presidential primary said he would ultimately, if he were a senator, vote to remove Trump from office.
But Michael Bloomberg wouldn't exactly be happy about it.
"We'd be much better off letting the voters decide who is president in this country," he said in an interview on NBC's "Today" show. "I'd have to swallow two or three times, but I would say I would vote to convict because there's so much evidence that he acted inappropriately."
Meet the lawyer behind Lev Parnas
Read this piece from CNN's Kara Scannell and Vicky Ward about how Lev Parnas' attorney, Joseph Bondy, has shaped the public perception of his client, the indicted Giuliani associate, into a key player in the impeachment trial.
Dershowitz logic
Alan Dershowitz is defending the Constitution and not the President, he says. But it's hard to keep up with his thinking. He'll present constitutional arguments on the President's behalf during the Senate trial, but he's made clear he's not completely a part of the defense team.
He's making these principled arguments about the Constitution, but when Clinton faced impeachment he held the opposite view, that a crime is not 100% required to impeach a president.
As he told Larry King on CNN in 1998, there "certainly doesn't have to be a crime if you have somebody who completely corrupts the office of president and who abuses trust and who poses great danger to our liberty. You don't need a technical crime."
With regard to Trump, he's not even willing to say whether power was abused. That's irrelevant, according to 2020 Dershowitz. Read this exchange from MSNBC:
Q: Do you believe that Donald Trump abused the power of his office, yes or no?
A: It's irrelevant. Abuse of power is not the criteria for impeachment, any more than dishonesty.
Q: Do you personally believe Donald Trump right now, with the evidence you've seen in front of you as one of his attorneys, abused his power, yes or no?
A: I'm not going to answer that question yes or no, it's irrelevant.
Kellyanne Conway: MLK Jr. would oppose impeachment
This seems like a stretch: Kellyanne Conway told reporters on Monday that she doesn't "think it was within Dr. King's vision to have Americans drag through a process where the President is not going to be removed from office, is not being charged with bribery, extortion, high crimes or misdemeanors" and that "anybody who cares about and justice for all -- today or any day of the year -- will appreciate the fact that the President now will have a full-throttle defense on the facts. And everybody should have that."
What are we doing here?
The President has invited foreign powers to interfere in the US presidential election. Democrats impeached him for it. A Senate trial is next. It is a crossroads for the American system of government as the President tries to change what's acceptable for US politicians. This newsletter will focus on this consequential moment in US history.
Keep track of action with CNN's Impeachment Tracker. See a timeline of events here. And get your full refresher on who's who in this drama here.
