1 of 21 | Donald Trump and Hillary Clinton greet each other after the first presidential debate at Hofstra University in Hempstead, N.Y. on Monday. Photo by Pat Benic/UPI | License Photo
HEMPSTEAD, N.Y., Sept. 26 (UPI) -- Donald Trump and Hillary Clinton spent much of a caustic debate Monday trading sharp barbs over the personal and the political, with both candidates questioning the other's fitness to serve as the next president of the United States.
From the economy to race relations, fighting terrorism and accusations of cover-ups in their personal dealings, Trump and Clinton spent 90-plus minutes criticizing each other.
The first terse exchange featured Clinton lobbing several personal jabs, dogging Trump for starting his business empire with a "$14 million loan from his father."
Trump responded, saying he got a "small loan" from his father which he turned into a multibillion-dollar company.
At times speaking about the economy, both candidates reverted to portions of the stump speeches they offer frequently on the campaign trail, with Clinton calling for greater investment in clean energy. Trump assailed trade deals he said benefit foreign competitors, specifically China and Mexico. He called for them to be renegotiated to more favorable terms for the United States.
"Secretary Clinton and others, other politicians, should have been doing this for years," he said.
When Trump referred to Clinton as "Secretary Clinton" it signaled a shift from much of his campaign rhetoric, referring to her by her government title as a former secretary of state, rather than the moniker "crooked Hillary" he uses frequently before supporters and on Twitter.
After Trump used the term "Secretary Clinton" he turned to her and asked: "Is that OK? I want you to be very happy, it's important to me."
Another contentious portion of the debate centered around Trump's role in questioning President Barack Obama's citizenship. The so-called "birther" movement grew to national prominence after Trump led a public attack on Obama, questioning whether he was born in Kenya, not America.
Trump said he now believes Obama's birth certificate, which the president released after Trump's repeated questioning of it, is legitimate and that Obama is a U.S. citizen. He also repeated a statement he made a week ago that the birther rumor started with Clinton's campaign against Obama in 2008 -- an accusation she denied, saying she saw firsthand how Obama was upset by it.
Clinton referred to it as a "racist birther lie."
Trump responded, saying Clinton's 2008 primary started the rumors.
"When you try to act holier than thou, it doesn't work," Trump said.
One of Trump's strongest moments came when he pressed Clinton for her reversal on the Trans Pacific Partnership, a large trade deal with Asian nations negotiated in part by Clinton as secretary of state that she previously supported and now opposes.
"You called it the gold standard of trade deals, you called it the finest deal you've ever seen, then you heard what I was saying about it and then you were against it," he said.
At one point in the debate, Trump referred to Obama as "your president" to Clinton -- a remark that drew condemnation from Clinton supporters on social media.
In another sharp exchange, Trump criticized Clinton for taking several days off the campaign trail to rehearse for Monday's debate.
"I've been to Philadelphia. I've been to Detroit. I've been all over. You decided to stay home," Trump said.
"I think Donald just criticized me for preparing for this debate," Clinton shot back. "Yes, I did. And you know what else I'm prepared for? I'm prepared to be president of the United States. And I think that's a good thing."
The candidates also tangled on foreign policy. Trump repeatedly talked over moderator Lester Holt, saying he was against the war in Iraq. Holt cited interviews where Trump said he was in favor of it. Trump raised his voice, arguing "let me finish, let me finish" and cited a number of other instances where he said the record showed his opposition, blaming the media for misrepresenting his position.
Monday's debate, held at Hofstra University on Long Island, promised to be the most watched political event in recent history, with a television audience of more than 100 million.
Coming into the debate, much was made of how the candidates would work to overcome the skepticism they faced with large swaths of the electorate. Polls show Clinton has struggled to prove to voters she is trustworthy, while Trump has struggled to prove to voters he has the temperament necessary for a successful presidency.
After a post-convention bump that saw Clinton holding a wide lead, the race has tightened significantly, raising the stakes for Monday night's debate. The UPI/CVoter tracking poll shows Clinton with a narrow lead nationally, but Trump leading in the Electoral College, and winning the presidency if the election were held today.
Twelve battleground states that will likely decide the election show the candidates running within 5 percentage points of one another, meaning a strong performance by one candidate -- or a serious stumble by another -- could have an immense impact on the trajectory of the race.
And while Election Day is still more than a month away, the aftermath of Monday's debate could be felt much sooner. The first early ballots will be cast in Illinois this week and over the next two weeks, seven states will begin early voting.
There are two more presidential debates scheduled, along with the vice presidential debate on Oct. 4 between Sen. Tim Kaine and Gov. Mike Pence.
Watch the full debate video below: