US President Donald Trump is having a bad week but hopes his first rally since March, this Saturday, will reenergise the reelection campaign. — AFP/VNA Photo

WASHINGTON — Donald Trump's presidency was in turmoil on Thursday after top ex-aide John Bolton declared him unfit for office in a bombshell book and the Supreme Court blocked a key part of his re-election vow to deport undocumented migrants.

The mounting drama around the Republican's already rocky re-election bid raised the stakes for his rally in Tulsa, Oklahoma, on Saturday - the first he will have held since the US coronavirus lockdown began, but mired in controversy over whether it is safe.

Trump's once supremely self-confident march toward a second term was already in a hole due to criticism over his responses to the coronavirus pandemic and nationwide anti-racism protests.

A Supreme Court ruling against his administration's bid to remove protections for hundreds of thousands of undocumented migrants classified as "Dreamers" struck another blow as Trump's re-election platform rests in large part on his promise to crack down on illegal immigration.

The ruling was doubly stinging because Trump has long boasted that his appointing of two justices succeeded in tilting the nation's top court to the right.

In an outburst on Twitter, Trump called this and other recent rulings he didn't like "shotgun blasts into the face of people that are proud to call themselves Republicans."

He also faced a blistering insider attack from Bolton, a lifelong Republican who saw Trump from up close as national security advisor.

"I don't think he's fit for office. I don't think he has the competence to carry out the job," Bolton told ABC News to promote his book The Room Where it Happened.

The book - which the White House is trying desperately to get blocked by court order - alleges that Trump asked Chinese President Xi Jinping for re-election help, obstructed justice and was no match for Russian President Vladimir Putin.

"Putin thinks he can play him like a fiddle," Bolton told ABC.

Secretary of State Mike Pompeo, who Bolton alleges shared his assessment of Trump, lashed out late Thursday in a statement that read, "I was in the room too."

"It is both sad and dangerous that John Bolton's final public role is that of a traitor who damaged America by violating his sacred trust with its people," Pompeo said.

Trump again attacked Bolton, calling him a "sick puppy" and dismissing the book as "fiction."

'Back on the road'? 

On Saturday, Trump will fly to Tulsa to hold his first campaign rally since March.

With his TV show background and natural populist flair, Trump is far happier in front of cheering crowds than in the formal settings of the White House.

He is "very excited to get back on the road," his advisor Kellyanne Conway said.

He'll be hoping that the razzmatazz and the energy of the 20,000-strong crowd will jumpstart his re-election, which polls show him currently losing heavily to Democrat Joe Biden. Even as Americans only slowly ease out of lockdown, several other rallies are already being planned.

But Tulsa is seeing a local spike in coronavirus cases and the city's main newspaper and the state health chief have warned that the huge crowd in an enclosed space could become a viral incubator.

A lawsuit filed in a court in Tulsa to try to stop the rally called it a virus "superspreader."

Oklahoma Governor Kevin Stitt, a Republican, said on Thursday "it's going to be safe and we're really, really excited." And the Trump campaign says it will take temperatures and distribute masks to rally goers.

Tellingly, though, it is also requiring anyone attending to sign a waiver that they won't hold organisers responsible for getting sick.

Trump's Tulsa rally suffered a further setback when it was scheduled originally for this Friday, which is the June 19th or "Juneteenth" anniversary of the end of slavery in the US.

Amid soaring racial tensions and anger from civil rights groups at his handling of the police violence protests, that struck the wrong tone and Trump was forced to shift to Saturday.

"Nobody had ever heard of it," he claimed in a Wall Street Journal interview published Thursday. "I did something good: I made Juneteenth very famous."

In fact, the White House annually puts out a statement commemorating the occasion, which is also marked by nearly all US states. — AFP