US President Donald Trump is in desperate need of a political boost after a fiasco of a campaign rally in Tulsa left him looking like a leader detached from the multiple crises gripping the United States.

In addition to the poor attendance, Trump's performance at the Oklahoma rally on Saturday had the air of a tired showman seeking to recapture the energy that drove him to an upset victory over Hillary Clinton in 2016.

US President Donald Trump is looking for a political boost after poor attendance at his Tulsa campaign rally
US President Donald Trump is looking for a political boost after poor attendance at his Tulsa campaign rally AFP / Nicholas Kamm

Tie undone, Trump's demeanor was sullen when he exited his helicopter on his return to the White House from the Tulsa event, which had been billed as the president's triumphant return to the campaign trail after the coronavirus pandemic put things on hold.

His gloomy appearance summed up the reality of the situation -- the November 3 election is 133 days away and his campaign is struggling.

And if Trump's tweets on Monday morning are any indication, a golf outing on Sunday did nothing to improve his mood.

Supporters of US President Donald Trump listen to him speak at his Tulsa campaign rally
Supporters of US President Donald Trump listen to him speak at his Tulsa campaign rally AFP / Nicholas Kamm

"RIGGED 2020 ELECTION: MILLIONS OF MAIL-IN BALLOTS WILL BE PRINTED BY FOREIGN COUNTRIES, AND OTHERS. IT WILL BE THE SCANDAL OF OUR TIMES!" he tweeted.

The tweet was Trump's latest salvo against mail-in voting, which is expected to take on added significance this year because of the coronavirus pandemic.

Trump has frequently claimed with no evidence that mail-in voting is particularly susceptible to fraud.

White House press secretary Kayleigh McEnany described President Donald Trump's Tulsa campaign rally as a 'huge success'
White House press secretary Kayleigh McEnany described President Donald Trump's Tulsa campaign rally as a 'huge success' GETTY IMAGES / Drew Angerer

Poll after poll shows Democratic presidential candidate Joe Biden with a comfortable lead over his Republican rival.

The billionaire real estate tycoon who crafted a stunning political upset in 2016 has shown his resilience on numerous occasions and cannot be counted out yet.

But confronted with twin crises -- the COVID-19 pandemic and nationwide protests for racial justice -- the 74-year-old president has appeared overmatched, unable, his critics say, to capture the pulse of the country.

Democratic presidential candidate Joe Biden is leading President Donald Trump in the polls
Democratic presidential candidate Joe Biden is leading President Donald Trump in the polls AFP / JIM WATSON

The strong economy which Trump has touted endlessly is in a shambles, ravaged by COVID-19.

IMAGESUS President Donald Trump's first campaign rally since the start of the pandemic in Tulsa, Oklahoma was marred by empty seats.
IMAGESUS President Donald Trump's first campaign rally since the start of the pandemic in Tulsa, Oklahoma was marred by empty seats. AFPTV / Sébastien VUAGNAT

With the coronavirus death toll in the United States reaching 120,000, Trump defied the advice of health authorities to hold a rally in an indoor stadium.

In his Tulsa speech, Trump said he had asked his staff to "slow the testing down" to prevent discovery of more virus cases, a remark his campaign staffers tried to pass off later as just a "joke."

He spent more than 14 minutes of his one hour and 43 minute speech explaining why he had haltingly descended a ramp following a speech at the West Point military academy.

Trump said he was wearing leather-bottomed shoes and was trying to avoid "falling on my ass."

Trump did fling a few barbs during his Tulsa speech at Biden, accusing his November opponent of being a "puppet" for both China and the "radical left."

But the president is still clearly searching for an angle of attack against a rival who is leading in the polls while making few campaign appearances.

As Trump struggles, his former National Security Advisor, John Bolton, is promoting a tell-all book that paints a damning portrait of the president.

"I hope (history) will remember him as a one-term president who didn't plunge the country irretrievably into a downward spiral," Bolton said in an interview with ABC News.

He expressed fears about potential damage to the world's flagship democracy if Trump wins a second term.

"The concern I have, speaking as a conservative Republican, is that once the election is over, if the president wins, the political constraint is gone," Bolton said.

Washington is rife with rumors of a potential shake-up in the Trump campaign with campaign manager Brad Parscale in the firing line. No changes have been announced for the moment.

White House Press Secretary Kayleigh McEnany, who promised when she took the position in May that she would never lie to journalists, pushed back on Monday at reports Trump was angry about the empty seats at Tulsa rally.

"I was with him after the rally, it was a huge success," she said. "His speech got rave reviews."