Vice presidential nominees JD Vance and Tim Walz will face off for their first and potentially only debate before the November election Tuesday, as the two Midwesterners with economic populist streaks strive to sway undecided voters in the tight race.

Set in New York, the debate will be the first time Vance, Donald Trump’s running mate, and Walz, Kamala Harris’ pick, appear on a stage together after relentless attacks against each other on the trail.

Walz, who was until recently a little-known Minnesota governor, endeared himself to Democrats even before Harris tapped him, when his interview clip mocking the Republican ticket as “weird” went viral. On the stump, he has pounced on Vance’s statements, such as his 2021 comments that the country is run by “a bunch of childless cat ladies who are miserable” to pitch that Democratic policies are better for Americans.

Vance, an Ohio senator who rose from poverty, has revelled in serving as Trump’s attack dog and messenger, such as by amplifying widely debunked claims that Haitian migrants in Springfield, Ohio, are eating pets. Calling Walz “Tampon Tim” for a Minnesota law requiring public schools to provide free menstrual products, Vance criticizes Democrats for being too extreme for the country.

Here’s what to know about the debate:

What time does the vice presidential debate start?

The 90-minute forum will kick off at 9 p.m. ET and will be moderated by CBS journalists Norah O’Donnell and Margaret Brennan.

What are the rules of the debate?

There will be no opening statements and no studio audience. Mics will be live throughout the event, although moderators can mute them at their discretion.

Walz and Vance must stay behind their podiums. Walz picked the right one, and Vance will be on the left. Pre-written notes are not allowed on stage, but they will have pens, paper and water.

Each candidates will have two minutes for closing statements, and Vance will deliver his last as determined by a coin flip that he won.

How do Tim Walz and JD Vance’s policies differ?

On the economy, immigration and abortion, the candidates contrast sharply.

In Minnesota, Walz’s support for increased spending, stricter regulations and higher taxes on the wealthy and companies won him the praise of unions and other progressive groups who say his policies make Minnesota a better place to live and work. Republicans and business groups say those plans hinder economic growth.

Walz, 60, supports a path to citizenship for some undocumented immigrants and has signed several bills protecting reproductive rights.

Vance, 40, on the trail is pitching Trump’s ever-growing litany of tax proposals that includes something for almost every American family. To pay for them, Trump has pledged to enact a 10 per cent across-the-board tariff on imports and even higher duties on Chinese-made goods. Most economists say that Americans would ultimately pay higher costs.

The former venture capitalist has embraced Trump’s hard-line immigration tactics, such as vowing to force mass deportations. He has characterized abortion-rights advocates as “sociopathic.”

Walz Vance favourability chart.

Who is more popular? What do pre-debate polls show?

Walz has a higher net favourability rating than Vance, according to the latest Bloomberg News/Morning Consult poll of registered voters in seven swing states.

A bigger share — 41 per cent — say they had a favourable view of the Democrat than those holding a negative one. Meanwhile, 46 per cent view the Republican negatively, compared to 37% holding favourable opinions, the poll released last week shows. For both candidates, the results are about the same as the previous month’s survey.

Is there going to be another presidential debate between Donald Trump and Kamala Harris?

It’s unlikely. Trump ruled out appearing at another debate with Harris two days after their first showdown in September. Public opinion polls, betting markets and even his allies said the Democratic candidate had the better performance during that forum.

That means Tuesday’s showdown could be the last highly viewed event that features both campaigns, potentially giving the vice presidential debate more weight than it generally has.

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