As the curtains draw open for tonight's showdown between Kamala Harris and Donald Trump, the stage is set for a battle of wits, policies, and character. But what should we be looking out for? Ahead of the debate, seven NBC News staffers weighed in on one big thing they'll be watching for. Here's what's on the agenda: How will the candidates address their vulnerabilities? Tonight, I'll be watching to see how each candidate addresses their biggest vulnerabilities on the issues. For Trump, it's abortion, and for Harris, it's her pivots on some key policy positions.

Who are the candidates talking to? One of the things I'll be looking for is which voters each candidate goes out of their way to address directly. Every campaign has a theory about what coalition of voters they need to win. What's striking is how both campaigns have the same challenges but, so far, appear to be going about their challenges differently.

Can Harris produce a viral moment? One of Harris' biggest moments from her debate with then-Vice President Mike Pence in 2020 came in the form of a response when he interrupted an answer and she said several times: 'I'm speaking.' It seemed to be something she had planned so we'll be watching to see if there's a similar response that she's prepared in case Trump speaks over her, though the muting of the microphones presents an additional challenge in how that may play out in real time.

Can Trump stick to his campaign strategy? Trump's campaign has a well-defined and thoroughly prepared strategy tonight: define Harris as 'dangerously liberal' and unfit to be president. Sound familiar? The challenge for the Trump campaign has long been for Trump, the candidate, to commit to this framework, one he has often appeared disinterested in.

What does Harris say about immigration? One thing to watch for is whether Harris continues her march to the center on immigration policy and how she communicates her more nuanced stance on building more of a border wall.

How does Harris project strength? Trump always tries to portray himself as the strongest of the candidates. He does it with his words and with his physical puffery. It's a trait that matters to voters — they want to know that a leader will protect them, and perceived strength is part of that. The question is: What will Harris do to project strength against Trump?

Is there a handshake? Something to watch for right at the beginning of the debate is whether Harris and Trump shake hands. A customary handshake to kick off a presidential debate is a way for candidates to set the tone and show mutual respect. But for the past three presidential cycles, shaking hands has not been a guarantee.

It's fitting that tonight's debate is taking place in Pennsylvania, because when it comes to the road to 270 electoral votes, the Keystone State is first among equals. With 19 electoral votes, it is the biggest single prize among the seven core battleground states — which also include Arizona, Georgia, Michigan, Nevada, North Carolina and Wisconsin. To offset fully the mathematical impact of a loss in Pennsylvania, each candidate would need to win at least two other battlegrounds.

The Stage is Set: What to Watch for in Tonight's Debate

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