Why Trump's 1st criminal trial could be his most politically significant ...

When it comes to the seriousness of the criminal charges against Donald Trump, the Stormy Daniels hush money case is the bottom of the barrel, says a former federal prosecutor.

But it's also likely to be the only criminal case against Trump that will make it to trial before Americans choose their next president in November. 

Jury selection began Monday in New York, marking the start of the first criminal trial of a sitting or former U.S. president. Trump is accused of committing 34 state felonies for allegedly falsifying business records in order to stifle stories about his sex life. The trial is expected to last six to eight weeks, according to a media advisory from the court.

Prosecutors allege Trump's former lawyer, Michael Cohen, paid porn star Stormy Daniels $130,000 US to stay quiet about her affair with Trump in the run-up to the 2016 election. Trump denies the affair, and has pleaded not guilty to all charges. 

It's one of four criminal cases pending against Trump as he heads into the U.S. presidential race as the presumptive Republican nominee. The others centre on allegations of election interference and the mishandling of classified documents. 

Attorney Jennifer Rodgers is law professor at New York University, a CNN legal analyst and a former federal prosecutor. Here is part of her conversation with As It Happens host Nil Köksal.

When we talk about potential witnesses, there's certainly a long list there. Who are you going to be watching for? Who do you think might be the most consequential? 

Certainly, Michael Cohen is central to the case. I think that's what everyone is watching for.

He's the key person. And of course, he famously broke with Trump. There's a lot of animosity between the two of them. 

And also, Michael Cohen is someone who pleaded guilty to a variety of federal offences, one of which was connected to this crime. So he's a convicted felon. One of the crimes he was convicted of is lying under oath. So, of course, there's going to be vigorous cross-examination on that. 

So for all those reasons — his importance as a witness, the animosity there, the aggressiveness that will be the cross-examination — Michael Cohen's testimony is going to be probably the most explosive. 

WATCH | Michael Cohen is problematic witness, says prosecutor: 

Star witness Michael Cohen is problematic and prosecution's theory is unique, former federal prosecutor Joseph Moreno says

Do we expect Donald Trump to take the stand? 

I don't think so. That would be a big risk for him. 

He's a famously undisciplined speaker and witness. And also, there's so much potential cross-examination there. You're allowed to cross-examine not only about the issue at hand … but you're allowed to cross-examine on impeachment material, including evidence of someone's reputation for dishonesty. 

And if you think about all of the things out there that show that Donald Trump has a reputation for dishonesty — you know, all of the verdicts against him, the fraud verdicts, media here has him at more than 30,000 lies during his time in office — there's just so much material there. So even if they get the judge to limit somehow the prosecutor's ability to go into all of that, which they might, I think it's too risky for Donald Trump to take the stand, given what kind of witness he is and what the cross-examination would look like. 

He's certainly making a statement already without saying a word. According to the New York Times' Maggie Haberman, writing today: "Trump appears to be sleeping. His head keeps dropping down and his mouth goes slack." Obviously, jurors haven't been selected yet. They won't be seeing that. But what do you think when you hear that? What impression might that send? 

That's surprising. I mean, maybe he was unable to sleep last night, and he's just really tired today. But I think once the jurors come in, he's going to want to be attentive and he's going to want to take this seriously. 

Jurors are always watching. I mean, there's going to be 18 of them, 12 plus the alternates. So someone is always going to be looking at him. 

So I'm sure lawyers will tell him to do what he needs to do, get caffeinated up or whatever, to be able to stay awake during everything. 

WATCH | Crowds outside Trump trial weigh in on: 

People outside the New York courthouse where Donald Trump's criminal trial began jury selection expressed differing stances on whether the former U.S. president is receiving fair treatment from the justice system.

What could it mean for him politically? If there's a conviction, he could still be the Republican nominee. [He] can still run, right? 

Our constitution only has three requirements for the presidency, and not being a convicted felon is not one of them. So he can still run. He can still win. He can still govern. 

I don't know what the voting public reaction will be to a conviction here if it happens. That's more for the political folks. And frankly, I don't even think they know. But we're a few weeks from finding out, and I guess we'll see what the polls say if, in fact, that comes to pass. 

This is, of course, only one of the cases that Donald Trump is facing, but likely the only one that's going to go to trial before election day. How do you weigh the significance of this particular case? 

If ... we were in position to have multiple trials before the election, then I would say that this one wouldn't be much of a blip, because the others are certainly more serious in terms of the conduct charged. 

But given that it's going to be the only one, I think it's going to be really important. 

It's going to be put to the voters, you know, if he's convicted: Do you want someone as the president who was a convicted felon, who did what these jurors agreed that he did?

Do you think his supporters will care if there's a conviction?

I don't think his hardcore supporters will care, because they really haven't cared about anything else. 

But he can't get elected with just his hardcore supporters. So, you know, the opposing view and the hope is that if he is convicted, there will be enough moderate Republicans and independents who will care and will say, "We don't want that person in office," and will either not vote or will vote for President [Joe] Biden, and that that will make the difference.