Grand Rapids, Michigan - Donald Trump, the Republican Party's White House nominee, returns to the campaign trail Saturday for his first rally since narrowly escaping assassination.

As Trump descends on battleground Michigan to stump in public with his vice presidential running mate J.D. Vance for the first time, Joe Biden's campaign is grappling with an internal Democratic Party revolt from senior lawmakers and donors calling on the 81-year-president to quit the race.

Biden has paused campaigning to nurse a case of Covid, while he and his inner circle engage in political firefighting as party stalwarts warn that by remaining on the ticket Biden could lead Democrats to defeat of the White House and both chambers of Congress.

Team Trump for its part is effervescent coming off this week's four-day Republican National Convention. The 78-year-old candidate's mission of demonstrating absolute control over the party and firing up his base appears accomplished.

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Dozens of the most ardent supporters were already lined up late Friday outside Van Andel Arena to be the first allowed through the doors.

"I'm going in and seeing one of the strongest S.O.B.'s there is, plain and simple," Sherri Bonoite, a 75-year-old grandmother from Michigan attending her first Trump rally, told AFP.

"Even a speeding bullet couldn't stop him. And he's what this country needs."

With Saturday's 5:00 PM indoor assemblage in downtown Grand Rapids, Trump is striding back on stage exactly one week after a 20-year-old gunman on a rooftop sprayed an outdoor Pennsylvania rally with bullets, killing one attendee and wounding Trump.

"I had God on my side," he told the convention Thursday, as he described how a bullet narrowly missed his head and grazed his ear.

Trump may not discuss details of last week's trauma, as he told the recent convention: "You'll never hear it from me a second time because it's actually too painful to tell."

Instead he will flaunt his new status as the party's flagbearer after officially accepting the nomination at the convention – and bask in the adoring reception in store for when he walks out to a partisan crowd.

He will almost certainly dive into the aggressive rhetoric of his typical campaign speeches, in which he assails the administration over immigration policy, inflation, the war in Ukraine, Israel's assault on Gaza, China policy, and oil drilling.

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All eyes however will be on the security posture, especially given how major questions remain over Secret Service lapses at the Pennsylvania event.

Trump will speak inside an enclosed 12,000-capacity sports facility that allows more complete control of a perimeter.

Security, nevertheless, is expected to be extra tight around Trump in the wake of the most egregious Secret Service failure in decades.

Trump also makes his debut campaign appearance with vice presidential pick Vance, a US senator from Ohio who at age 39 could appeal to younger conservative voters.

And Vance's blue-collar connection could help Trump, a billionaire businessman, win over critical swing states like Michigan, Pennsylvania, and Wisconsin.

Meanwhile, Biden's campaign is lurching from crisis to crisis.

A disastrous debate performance against Trump three weeks ago sparked panic about his age and health, and whether the veteran politician has the capacity to stave off a resurgent Trump in November.

Most polls show Trump on course for an Oval Office return.

More than 30 House Democrats and four senators have now called on Biden to drop out, and several party luminaries including Barack Obama have reportedly urged the president to reconsider his decision to stay in the race.