Takeaways from Kamala Harris and Donald Trump's first — and maybe only — debate

• Kamala Harris and Donald Trump are debating for the first — and maybe only — time in Philadelphia.
• It's the highest-stakes moment of the presidential campaign yet.

Vice President Kamala Harris and former President Donald Trump met for their first debate on Tuesday night.

The high-stakes face-off, taking place at the National Constitution Center in Philadelphia, may be the two candidates' only debate of the election — they have not yet agreed to meet for a second time.

Here are the biggest takeaways from the debate so far.

Kamala Harris made a point to shake hands with Trump

For the first time since 2016, the two presidential candidates shook hands on the debate stage.

It was Harris who made the first move, crossing the stage toward Trump to greet him at the outside of the debate.

"Kamala Harris, good to debate with you," the vice president could be heard saying.

Harris often sneered at Trump as he spoke

Despite the Harris campaign's best efforts, each candidate's microphone remained muted while the other was speaking. But that doesn't mean that the Vice President didn't communicate with viewers as Trump spoke.

In fact, Harris could often be seen on the split-screen staring over toward Trump with a bewildered look, narrowing her eyes and shaking her head at times. When Trump dubbed her a Marxist, she even appeared to laugh, placing her hand on her chin.

That's a choice, given the performative aspects of a high-stakes presidential debate. Harris is betting that showing active disdain for Trump will play well with viewers.