Campaign enters final stretch

Donald Trump and his Democratic rival Joe Biden traded tough blows Monday as the White House race entered its final stretch, with the Republican leader branding his opponent "stupid" -- and the Democrat firing back that the president lacked the "guts" to tackle the Covid-19 pandemic.

As Biden and his running mate Kamala Harris took their campaign message to must-win swing states Pennsylvania and Wisconsin, the president convened a surprise news conference at the White House.

In a freewheeling and grievance-laden performance, Trump once more teased the possibility of a Covid-19 inoculation by Election Day -- something experts say remains unlikely -- and accused his opponents of playing politics with a vaccine after Harris said she would not take his word alone on its safety.

Touting an upswing in job creation -- after tens of millions lost jobs -- and claiming the US is turning the corner on the pandemic, he called Biden "stupid," saying he "wants to surrender our country to the virus, he wants to surrender our families to the violent left-wing mob, and he wants to surrender our jobs to China."

Labor Day traditionally kicks off the final sprint of the campaign, with less than two months until the November 3 election -- but the rival campaigns have been knocked off stride by multiple layers of turmoil, from the pandemic to the struggling US economy to deep racial unrest.

Addressing an event in the swing state Pennsylvania, Biden hit back at Trump, charging that "he didn't have the guts to take on Covid."

"We know he's been great for his rich friends, but he hasn't been so great for the rest of us," charged Biden, who went on to assail Trump over a report in The Atlantic magazine that he has disparaged the military and its veterans.

"He's downright un-American," Biden fumed.

Biden's visit to Pennsylvania on Monday kicked off a flurry of travel to battleground states this week by both Biden and Trump as some opinion polls show the race tightening with less than 60 days to go until the Nov. 3 election.

Polls in Pennsylvania, which Trump won narrowly in 2016, have consistently put Biden in the lead, but averages show that margin narrowing to roughly 4 to 5 percentage points, down from about 8 points in late June.