Harris and Trump are sparring in the high-stakes showdown.
The first presidential debate between Vice President Kamala Harris and former President Donald Trump turned into a heated matchup that lasted more than 90 minutes.
The night started with a handshake initiated by Harris, but quickly escalated as the vice president bashed Trump over his policies and comments, contending that it was time to "offer is a new generation of leadership for our country."
Trump criticized Harris throughout the debate on topics such as Afghanistan and immigration issues, drawing comparisons between the vice president and President Joe Biden.
With Election Day just eight weeks away, the debate came at a critical point as polls show a neck-and-neck race between the candidates.
Vivek Ramaswamy, a former presidential candidate and vocal Trump supporter, said the former president would win a debate centered around policy.
"I think a win looks like a policy-focused debate," he said.
"If we have a policy-focused debate, Donald Trump hits it out of the park."
-ABC News' Tal Axelrod
"Race for the White House," ABC News' prime-time pre-debate special, premiered at 8 p.m. ET.
The special is anchored by chief global affairs correspondent and "This Week" co-anchor Martha Raddatz, chief Washington correspondent and "This Week" co-anchor Jonathan Karl, chief White House correspondent Mary Bruce and senior congressional correspondent Rachel Scott.
You can watch live on ABC, ABC News Live, Disney+ and Hulu.
Tonight's debate is being held at the National Constitution Center in Philadelphia.
Pennsylvania has emerged as a central battleground once again after sealing President Biden's victory over Trump in 2020.
Right now, Harris and Trump are separated by less than 1 percentage point in 538's polling average of the Keystone State.
Of the seven or so states believed to be in play this cycle, Pennsylvania holds the most electoral votes at 19.
In the most recent ABC News/Ipsos poll, Harris had an advantage over Trump when it came to who Americans think has better "physical health" and "mental sharpness" to serve effectively as president.
Trump has recently gotten attention for his rambling and often-incoherent speaking style, and while that's nothing new for him, this will be his first time directly facing a new opponent, who's nearly 20 years younger than him. Whether or not Trump's age or mental acuity come up explicitly in tonight's debate, how he handles himself — and how viewers respond afterward — could help him put some of those concerns to rest, or exacerbate them and give Harris an opening.
—538's Tia Yang
