Trump vs. Harris: The economic topics to watch during tonight's debate

Tonight, Kamala Harris and Donald Trump will meet for the first time — literally, as they’ve never met in person before — for a high-stakes debate in Philadelphia with economic issues likely to be front and center.

What is well known is how each side is likely to attack the other on fiscal issues. How they respond is where it could get interesting.

Former President Trump is highly likely to once again charge that Harris is a communist, echoing a favorite and baseless line in recent weeks that he's running against "Comrade Kamala." Vice President Harris is sure to shoot back with charges that Trump's plan could tip the country into a recession and send prices through the roof via his tariffs plans.

And the final day before the debate included plenty of gamesmanship, with the Harris campaign putting up billboards in Philadelphia and releasing a new ad Tuesday morning trolling Trump over crowd sizes to try to get under his skin.

The Trump campaign had responded with an argument that Harris has a "high bar to clear" given how new she is to the race. Senior adviser Jason Miller added that things could be unpredictable. He told reporters ahead of the debate, "You can't prepare for President Trump; there's just no way to do it," comparing it to trying to box Floyd Mayweather Jr. or the late Muhammad Ali.

What few observers are expecting is a high-minded discussion of economic plans.

Read more: Trump vs. Harris: 4 ways the next president could impact your bank accounts

En esta combinación de fotos se muestra al expresidente y candidato presidencial republicano Donald Trump el 15 de agosto de 2024, en Bedminster, Nueva Jersey, y a la vicepresidenta y candidata presidencial demócrata Kamala Harris en un evento de campaña el 16 de agosto de 2024, en Raleigh, Carolina del Norte. (AP Foto)
Will they shake hands? Former US President and Republican presidential candidate Donald Trump and Vice President and Democratic presidential candidate Kamala Harris. (Associated Press) (ASSOCIATED PRESS)

Indeed, the expectations are for a tense confrontation that is likely, perhaps more than anything else, to be most memorable for the name-calling and how each responds.

Nonetheless, the back-and-forth tonight is also expected to cover a wide variety of terrain, from abortion to immigration to Trump's continued focus on election lies.

But here's some of the pocketbook issues to watch.

One of former President Donald Trump’s favorite digs these days is to talk about "Comrade Kamala" Harris. It's a constant feature on his social media with his last invocation of the moniker coming early Tuesday morning, It’s a blatantly false nickname that Trump has stuck with in recent weeks as an apparent way to signal his overall charge that Harris is a candidate of the far left who would wreck the economy if she wins.

Harris has, it seems, spent much of the last week preparing to rebut the charge with a series of moves to moderate her economic platform.

Last week, it was a small business plan that included a tenfold increase in tax credits for new entrepreneurs and a split with Biden on long-term capital gains.

Then this week, her website debuted an issues page with the first chapter devoted to her "opportunity economy" plans.

Read more: Kamala Harris proposes tax credit for first-time home buyers. What about Trump?

TOPSHOT - US Vice President and Democratic presidential candidate Kamala Harris gestures as she arrives to speak at a campaign event at the Throwback Brewery, in North Hampton, New Hampshire, on September 4, 2024. (Photo by Joseph Prezioso / AFP) (Photo by JOSEPH PREZIOSO/AFP via Getty Images)
Vice President and Democratic presidential candidate Kamala Harris arrives to speak at a campaign event in North Hampton, N.H., on Sept. 4. (JOSEPH PREZIOSO/AFP via Getty Images) (JOSEPH PREZIOSO via Getty Images)

The series of releases aimed to underline how, as Harris put it in a recent speech, her White House would be one that "leads to broad-based economic growth and ... creates jobs, which makes our economy stronger."

The effort to define Harris in voters' minds is a central task for both sides, especially after a weekend survey by The New York Times and Siena College found that 28% of likely voters say they feel they need to know more about Harris.

Harris also outlined her overall debate message during a break in preparations on Saturday in Pittsburgh, saying: "It’s time to turn the page on the divisiveness. It’s time to bring our country together."

Whether she can make that case and also convince voters of her business bona fides with Trump standing just a few feet away is something that will be closely watched.

Trump may also need to offer new details Tuesday night on his plans for tariffs.

The former president has promised to levy duties of 10% to 20% on US trading partners and higher rates of 60% on China if he is returned to the Oval Office.

That could lead to additional costs of up to $3,900 for a typical family each year, according to an estimate from Brendan Duke of the left-leaning Center for American Progress.

The Peterson Institute for International Economics has also run the numbers and found a somewhat smaller tab, but the Harris campaign has seized on that $3,900 stat to charge again and again in recent weeks that Trump is proposing something akin to a "national sales tax."

Read more: What are tariffs, and how do they affect you?

It’s a charge that Trump has repeatedly brushed off in recent weeks, but he could be directly confronted with the issue by Harris or the debate moderators — ABC’s David Muir and Linsey Davis.

And Harris may be looking for such a direct confrontation. In a recent New York Times interview, Hillary Clinton said she's spoken with Harris, and her advice is Trump "can be rattled. He doesn’t know how to respond to substantive, direct attacks."

TOPSHOT - Former US President and Republican presidential candidate Donald Trump takes part in a town hall moderated by Fox News broadcaster Sean Hannity at the New Holland Arena in Harrisburg, Pennsylvania, on September 4, 2024. (Photo by Mandel NGAN / AFP) (Photo by MANDEL NGAN/AFP via Getty Images)
Former US President and Republican presidential candidate Donald Trump smiles during a town hall moderated by Fox News in Harrisburg, Pa., on Sept. 4. (MANDEL NGAN/AFP via Getty Images) (MANDEL NGAN via Getty Images)

Trump is unlikely to back away from his plans, based on a recent appearance at the Economic Club of New York. The former president doubled down on his tariff ideas in that speech, even in the face of persistent business world worries about the instability that might come with another series of Trump-led trade wars.

All told, "we expect tariffs and taxes to feature prominently as topics of discussion," the analysts at Raymond James wrote in a recent preview for clients. But they noted that both candidates could be light on details, with Harris in particular incentivized "to remain light on policy specifics where she can through November."

Perhaps the question is whether the fight over debate rules will force the candidates to provide more detailed answers from the candidates when these topics come up.

After weeks of back-and-forth, the Harris campaign has assented to mics that are muted when it’s not a candidate’s turn to speak. Each candidate will be allotted two minutes to answer each question, with an additional minute set aside for possible follow-ups, according to the published plans for the debate.

It was a set of rules first agreed to in the June debate in part to provide candidates with time and space to explain their policies without interruption.

What remains to be seen is if the candidates use the time to break new ground on their policies from taxes to energy to fighting inflation.

"Any incremental new information we get is helpful, but I'm holding my breath that we're going to learn a lot," Stifel’s chief Washington policy strategist, Brian Gardner, noted in a recent webinar appearance.

This post has been updated with additional developments and context.

Ben Werschkul is Washington correspondent for Yahoo Finance.

Click here for political news related to business and money policies that will shape tomorrow's stock prices

Read the latest financial and business news from Yahoo Finance