Kamala Harris and Tim Walz debut as presidential ticket in front of supporters in Philadelphia

Kamala Harris and her newly elected running mate, Tim Walz, held their first joint rally Tuesday in Philadelphia, Pennsylvania, aimed at making themselves known to Americans just three months before the presidential election.

The Democratic candidate and the one who would become her vice president in case of victory in the vote next November 5 have little time to convince voters.

In an auditorium packed with enthusiastic Democrats, who gave a warm welcome to the tandem, accompanied by their respective spouses, Harris warned that this campaign "is not only a combat against Donald Trump", the Republican rival.

"It's a fight for the future," she said.

His running mate, Tim Walz, elected earlier Tuesday, lashed out at the Republican mogul.

"Donald Trump sees the world differently. He has no idea about service because he's too busy serving himself," Walz said.

This first joint rally in Pennsylvania, a pivotal swing state for the next White House occupant's victory, is the first of a multi-day tour of several pivotal states.

Atypical trajectory

Ex-military National Guard with an atypical background, Walz comes from a rural background unlike the vice president.

The governor has embraced progressive measures, such as legalizing cannabis for recreational use, restrictions on gun purchases or expanding federal protections for workers.

President Joe Biden, who turned the campaign around by dropping out of re-election on July 21 in favor of his vice president, enabled Walz's election.

However, Trump's campaign team immediately called Walz a "dangerous extremist leftist".

"Tim Walz's balance sheet is a joke," the mogul's running mate, JD Vance, told supporters also gathered in Philadelphia.