AMNA NAWAZ: The first GOP presidential debate will play out in prime time tomorrow, even as the leading contender for the nomination plans to be a no-show.

Lisa Desjardins brings us the latest on what to expect from this historic debate.

LISA DESJARDINS: How do you debate a front-runner who doesn't show up?

That's the question for the eight candidates appearing tomorrow in Milwaukee.

Here they are in their stage positions announced today.

The debate is a major moment, as well as a test for the Republican Party and for the impact of debates themselves.

Gail Gitcho is a GOP strategist and presidential campaign veteran.

A disclosure: She previously worked for candidate Vivek Ramaswamy.

She's been in the room for the Republican debate prep in the past, and she joins me now.

Gail, what are the stakes for this debate, and for whom?

GAIL GITCHO, Republican Debate Coach: Well, I think that the stakes are high for everybody.

But, in particular, they're the highest for Governor Ron DeSantis, because he's restarted his campaign a couple of times.

He's done some shakeups.

And I think everybody is going to take potshots at him, just as they have been throughout these last several weeks.

So I think the stakes are highest for him.

But he also has a really great opportunity to throw some punches back if he chooses to.

But, really, what he should be doing is driving his message as to why key would be better, more electable than President Trump.

LISA DESJARDINS: You mentioned potshots and punches.

Those are things that former President Trump excelled at generally in debates, but few others could land punches on him.

One who did was Carly Fiorina and 2015 asked about his criticism of her face.

She also brought up the "Access Hollywood" tape and the former president's own words to Billy Bush about how he felt he could sexually grab women.

Here's what she said.

CARLY FIORINA (R), Former Presidential Candidate: Mr. Trump said that he heard Mr. Bush very clearly and what Mr. Bush said.

I think women all over this country heard very clearly what Mr. Trump said.

(APPLAUSE) LISA DESJARDINS: I bring this up to ask you, what does work in this environment in terms of landing a criticism or a punch on someone who's opposing you?

GAIL GITCHO: You know, I remember that debate.

And that was the cleanest punch that anybody ever landed on President Trump.

I was with Bobby Jindal at the time.

And he was not on the stage with President Trump.

But we were on the campaign trail.

And everybody, not just our campaign, but all the campaigns were trying to figure out, how do we land something?

Because when you do these silly attacks or these silly insults, he's just going to punch right back.

So, if you're going to punch at Trump, you better landed.

And nobody did that better than Carly Fiorina that cycle.

LISA DESJARDINS: And Trump won't be there tomorrow night.

That is an issue, because the candidates there will be asked about him.

Going back again to that 2016 cycle, here's Ted Cruz in a debate that President Trump boycotted then.

Here's how he tried to handle that.

SEN. TED CRUZ (R-TX): Let me say, I'm a maniac.

And everyone on this stage is stupid, fat and ugly.

And, Ben, you're a terrible surgeon.

(LAUGHTER) SEN. TED CRUZ: Now that we have gotten the Donald Trump portion out of the way... (LAUGHTER) LISA DESJARDINS: How do you think these candidates will handle the elephant not in the room?

GAIL GITCHO: You know, I think that's what their debate prep is about now.

There are a couple of candidates that are probably going to go straight at Trump, and, namely, Chris Christie, because it's not in his DNA to do anything but go straight at Trump.

And we have seen that on the campaign trail.

We have seen that for a couple of years now.

But I think the other person that has the opportunity to take him on very specifically on accomplishments is Governor DeSantis.

But what he could do tomorrow night is say that he handled the pandemic better when he was governor - - during his time as governor of Florida.

He can say, Donald Trump, while you were shutting down the country, I was opening up Florida.

So he's really the only person on that stage with the kind of executive experience where he's able to say, I did it better.

LISA DESJARDINS: Who else are you watching?

A lot of folks are going to be watching Vivek Ramaswamy, a candidate you know well.

This is a moment not just about this election cycle, but maybe future ones.

Who are you watching?

GAIL GITCHO: I think so.

I really liked Tim Scott, because this message is so different from anybody else on the stage.

He has a message of positivity, of optimism, because that's who he is.

He's sort of built for this, because he has the resources to go the distance, not just this cycle, but next cycle.

But he's also got this life story to tell that Republican voters are really yearning for, because we haven't heard it in so long.

This optimistic message has gotten pretty far in the Iowa polls, so far, at least.

LISA DESJARDINS: All right, Gail Gitcho, thank you so much.

We will all be watching tomorrow night.

GAIL GITCHO: Thank you.

Have a great night.