(NewsNation) — Looking at the past debates of both presidential candidates can give an indication of what Tuesday night’s matchup may bring.

While the public has not seen Vice President Kamala Harris and former President Donald Trump go toe-to-toe on the debate stage, they have debated other candidates many times in the past. This may give a better indication of what their styles are like.

Analysts can look to at least two previous debates to predict performance. One includes former President Trump’s debate with President Joe Biden a few months ago. The other includes Vice President Harris’ debate with then-Vice President Mike Pence four years ago.

The former president was more disciplined while debating President Biden than he had been previously, and on the other hand, the current vice president appeared respectful yet assertive against the former VP.

However, both Harris and Trump are very different candidates now. Trump can sometimes tie himself in knots, says NewsNation correspondent Robert Sherman, while Harris is not going up against the more reserved Pence.

That’s the future, which can’t be fully predicted, but the past and present can offer some insight. Currently, Harris has spent the weekend in Pittsburgh going through her debate preparation, and she has made a couple of public appearances around the city as well. Her debate preparation has focused on watching tapes of what the former president has said in the last couple of debates, trying to determine what could come her way Tuesday night.

In a 2019 Democratic presidential primary debate, then-candidate Rep. Tulsi Gabbard went on offense against Harris.

Trump could emulate Gabbard in his preparation for the debate, as his style is known to be offensive, finding ways to turn the conversation around, pivot and hit his opponent.

The debate in Philadelphia will be at 9 p.m. ET Tuesday, Sept. 10, and air on ABC News.