For the past 3½ years, Vice President Harris has carried out President Biden’s agenda around the globe, traveling to 21 countries, working with allies to combat authoritarianism.

But now, as the Democratic presidential nominee, there are questions about how Harris herself sees the world and the United States’ role in it — and what her foreign policy would look like if she wins the election in November.

It’s an issue likely to be front and center in Tuesday’s debate with former President Donald Trump. Republicans have sought to blame Harris for what they cast as the foreign policy failures of the Biden administration — from the chaotic withdrawal in Afghanistan to the number of migrants at the southern border

“If Kamala wins, foreign leaders will treat America’s president as a joke,” Trump said at a rally in Montana last month. “They already do.”

Harris has tried to present a contrast with Trump

Harris, for her part, is trying to contrast her vision for the world with Trump, while offering ever-so-subtle distinctions with Biden. Her speech at the Democratic convention last month was aimed at showing how she would lead as commander in chief.

“As president, I will never waver in defense of America’s security and ideals, because in the enduring struggle between democracy and tyranny, I know where I stand and I know where the United States belongs,” Harris said.

Earlier this year at the Munich Security Conference, before she was the nominee, Harris told European leaders that “isolation is not insulation.” It was a reference to Trump’s world view. During his time in office, the former president slapped tariffs on allies and threatened to pull out of NATO.

In contrast, the day after she was inaugurated, Harris made her first international call as vice president to the head of the World Health Organization to discuss the administration’s decision to rejoin the group. Trump had pulled out of the WHO during the pandemic.

How Harris differs from Biden

As vice president, Harris made a point of visiting Africa — something Biden promised to do, but has not yet done. A senior administration official who spoke on the condition of anonymity to describe Harris’ work behind the scenes said she has had an emphasis on the Global South in her work.

Harris has endorsed and echoed Biden’s emphasis on managing competition with China and supporting Ukraine in its fight against Russia.

When it comes to the war in Gaza — one of the biggest foreign policy challenges for whoever wins the election in November — Harris has said Israel has a right to defend itself and that she will ensure it has the “ability” to do so.

At the same time, she was among the first voices in the administration to emphasize the humanitarian suffering of Palestinians in Gaza. But to date she has offered little indication of how her rhetorical empathy may translate into policy.

While their world views largely align, Harris and Biden have different personal and professional experiences that inform their decisions, aides said.

Harris is the daughter of immigrants — an Indian mother and a Jamaican father. “She is not of the Cold War generation,” said Nancy McEldowney, who served as Harris’ national security adviser during the early part of the Biden administration.

“She is very mindful of the fact that the world has changed in fundamental ways over the course, not just of the last 50 years, but of the last five years,” McEldowney said.

Harris came to Washington in 2017 as a politician who had built her career domestically as a prosecutor.

The then-newly minted senator for California joined the Intelligence Committee, and that experience was critical in shaping her thinking. The committee launched a multiyear investigation looking into Russia’s interference in the 2016 election.

“She was really kind of thrown into what was the most critical national security issue at that time, which was defending against Russia’s threat to our democracy,” said Halie Soifer, who worked as Harris’ national security adviser at the time and is now the CEO of the Jewish Democratic Council of America.

Harris’ prosecutorial background informs her world view

Harris’ foreign policy developed through her work on intelligence and cyber security. And she became particularly focused on international rules and norms, said Rebecca Bill Chavez, co-director of foreign policy for Harris’ 2020 presidential bid.

It’s a throughline Chavez, now CEO of the Inter-American Dialogue, says she has seen with the vice president’s work in Central America.

“She’s been very active in working with the countries of Guatemala, El Salvador and Honduras in pushing for the rule of law and for judicial security,” Chavez said.

Her prosecutorial background is a factor in how she thinks about international issues. McEldowney recalls that on international trips, Harris wanted to see the highest court “to see where it was located, how it was presented, and to get a frame of how countries dealt with the laws that govern society.”

She says Harris also thinks a lot about technology and how that intersects with foreign policy.

“She has spent much of her time as vice president focused on issues that she knows are going to be significant going forward, such as cyber and AI and space,” McEldowney said.

NPR’s Gus Contreras and Kai McNamee contributed to this story.