Perhaps the most anticipated debate in American presidential politics Monday night ended as it began: with two candidates offering such diametrically opposed messages that at times it seemed like they were speaking about different countries.

Donald Trump and Hillary Clinton disagreed over trade policy, tax reform, climate change and foreign policy. Clinton displayed a mastery of details. Trump made his case for being an outsider. He called her “Secretary Clinton.” She called him “Donald.”

How it will all sit with undecided voters frustrated by a choice of two candidates they strongly dislike remains an open question.

Clinton cast the election as a choice between a political veteran intent on helping the middle class and a self-serving politician who cannot be trusted.

“I want to invest in you. I want us to invest in your future,” she said. “You have to judge us. Who can shoulder the immense, awesome responsibility of the presidency? Who can put into action the plans that will make your life better?”

Trump channeled the frustration of voters left behind by a dramatically shifting modern economy and by politicians paralyzed by partisan gridlock.

“Our jobs are fleeing the country. They’re going to Mexico. They’re going to many other countries,” he said. “We have to stop our jobs from being stolen from us. We have to stop our companies from leaving the United States.”

The 90-minute, commercial-free debate was the first of three exchanges scheduled ahead of the Nov. 8 election. Many voters, including in Florida, have already started to vote, and Monday’s big event at Hofstra University in Long Island was expected to draw near-record viewership. Polls nationally and in Florida show an essentially tied race after a long, tumultuous campaign.

The moderator, Lester Holt of NBC News, largely let Clinton and Trump go after each other. Much controversy had stirred ahead of the debate about whether the referee should step in and fact-check the candidates. Holt did so at times, such as when Trump falsely insisted he never supported the Iraq War (“mainstream media nonsense,” Trump said), but Holt also left much of the correcting up to the candidates. Clinton let several of Trump’s previously disproven statements go unchallenged.

Other than a passing mention, immigration — an issue at the heart of Trump’s candidacy — did not come up.

Clinton, a debate veteran, had prepared diligently for the evening, while Trump had boasted that he might wing it. Their divergent approaches showed on stage.

“I think Donald just criticized me for preparing for this debate, and yes, I did,” Clinton said. “And you know what else I prepared for? I prepared to be president — and I think that’s a good thing.”

Trump spent seemingly long periods of time discussing topics unlikely to help him win over women, minority and moderate voters whom he has so far struggled to attract. He stood by derisive past remarks about Rosie O’Donnell. He defended insisting for years — falsely — that President Barack Obama was not born in the U.S. He denied calling global warming a Chinese hoax — even though a tweet saying as much was still posted to his Twitter account.

When Holt asked Trump why he has yet to release his tax returns, flouting decades of tradition among presidential candidates, Trump briefly pivoted to Clinton’s private email servers as secretary of state — “That was more than a mistake. That was done purposely,” he said — but then inexplicably returned to the tax question.

Yet Trump was particularly effective at the start of the debate, the period most likely to draw the largest number of views. That portion involved trade, which is central to Trump’s platform.

Although Trump took on a more aggressive stance — he scoffed, interrupted, sighed “Ugh” — Clinton seemed eager to needle her opponent, often with a smile, about his inherited wealth and business dealings.

“Donald was one of the people who rooted for the housing crisis. He said back in 2006, ‘Gee, I hope it does collapse because then I can go in and buy some and make some money,’” Clinton said.

“That’s called business, by the way,” Trump interjected.

When Clinton highlighted Trump’s repeated business bankruptcies, he retorted: “I take advantage of the laws of the nation.”

She dismissed his approach to the economy as “Trumped-up trickle-down” and hit Trump for failing to pay contractors in some of his real-estate developments. He didn’t deny doing so — “Maybe he didn’t do a good job and I was unsatisfied with his work” — and didn’t deny her accusation that perhaps he won’t release his tax returns because he hasn’t paid a federal income tax.

“Typical politician — all talk, no action, sounds good,” said Trump, who at one point plugged his new hotel in Washington D.C. “Doesn’t work, never gonna happen.”

Trump maintained he’s guided by a gut-level approach to business that would translate to the White House.

“I have much better judgment than she does,” he said. “There’s no question about that. I also have a much better temperament than she has, you know?”

Toward the end of the debate, Trump, who is older than Clinton, continued to question her physical “stamina,” an issue she dismissed by noting that she visited 112 countries as secretary of state — and spent 11 hours testifying before a congressional committee, which investigated the attack on Americans in Beghazi, Libya.

She turned the question into one of gender, referring to Trump’s past derogatory remarks about women, including Alicia Machado, a former Miss Universe from Venezuela who says he once called her “Miss Piggy.” Machado, who now lives in Miami and recently became a U.S. citizen, has said she is voting for Clinton.

Trump, as he has done successfully throughout the campaign, shrugged it off.

“I want to make America great again,” he said. “We are a nation that is seriously troubled.”