Former US president Barack Obama launched a blistering attack on Donald Trump on Wednesday as he hit the campaign trail on behalf of Democratic candidate Joe Biden with less than two weeks to go before the election.
Speaking at a drive-in rally in Philadelphia, Pennsylvania, Mr Obama offered his fiercest critique yet of his successor, taking aim at Mr Trump's divisive rhetoric and his track record in the Oval Office.
"He hasn't shown any interest in doing the work or helping anybody but himself," Mr Obama said.
Mr Obama, who governed for two terms and remains one of the most popular figures in the Democratic Party, blasted Mr Trump for his handling of the pandemic and noted that the president himself became infected.
"Donald Trump isn't suddenly going to protect all of us. He can't even take the basic steps to protect himself," Mr Obama said.
Mr Obama's appearance filled a gap left by Mr Biden, his former vice president, who since Monday has been at home in Delaware to hold meetings and prepare for his debate with Mr Trump in Nashville, Tennessee, on Thursday.
The drive-in rally was held in the car park of Citizens Bank Park, the baseball stadium in Philadelphia, with the city's skyline visible in the distance.
It was the largest event that the Biden campaign has staged during the outbreak.
About 280 vehicles were spread throughout the area, with big screens placed to allow those in attendance to watch the former president.
With a recent Reuters/Ipsos poll showing Mr Biden with a lead of only 4 percentage points in Pennsylvania, Mr Obama warned Democrats against complacency.
"We've got to turn out like never before. We cannot leave any doubt in this election," he said.
Four years ago, Mr Obama participated in a rally in Philadelphia with Hillary Clinton, the Democratic nominee at the time, a day before the election, only for Mr Trump to narrowly take the state.
The Biden campaign considers winning Pennsylvania to be a top priority.
Americans are voting early at a record pace this year, with 42 million ballots cast both by mail and in person before the November 3 election.
The record early vote so far represents about 30 per cent of the total ballots cast in 2016, according to the University of Florida's US Elections Project.
After Mr Obama spoke, Mr Trump held a rally in North Carolina, another battleground state where opinion polls show a tight race.
Mr Biden's running mate, Kamala Harris, was also in North Carolina to rally voters in Asheville and Charlotte.
Even though the speech on Wednesday marked Mr Obama's 2020 campaign debut, his support has been essential for Mr Biden.
Mr Obama appeared at joint fund-raisers with Mr Biden and Ms Harris and his network of well-connected former aides has been instrumental in helping the campaign to outdo Mr Trump in bringing in donations.
The Biden campaign is hopeful that Mr Obama will commit to more events before the election.
The last days of campaigning are taking place during a surge in new Covid-19 cases and a sharp increase in the number of virus patients being admitted to hospitals in battleground states, including North Carolina and Pennsylvania but also Wisconsin, Ohio and Michigan.
Pennsylvania averaged 1,500 new cases a day over the past week, a level it has not reported since April, according to analysis by Reuters.
North Carolina averaged 2,000 new cases a day in the past week, its highest level since the outbreak began.
The virus has killed more than 221,000 people in the US.
Polling shows a majority of voters are disappointed in the way Mr Trump has handled the pandemic, which he repeatedly said would disappear on its own.
With Mr Biden is leading in national polls, the second and final presidential debate on Thursday gives Mr Trump an opportunity to change the trajectory of the race.
