ORLANDO, Fla. (AP) - Jabbing at the press and poking at the political establishment, President Donald Trump officially kicked off his reelection campaign Tuesday at a Florida rally where he exhorted thousands of rollicking supporters to keep advancing his political movement to put America's "own citizens first."

At the Amway Center in Orlando, Florida, Trump reminisced about his 2016 campaign, describing it is as a "great political movement" and "a defining moment in American history."

And he said he had fundamentally upended Washington, staring down "a corrupt and broken political establishment" and restoring a government "of, for and by the people."

Vice President Mike Pence offered a more direct pitch.

"We're here for one reason and reason only: America needs four more years of President Donald Trump," he said, prompting a "Four more years!" chant.

"It's on," Pence added. "Time for round two."

Of course, Trump never really stopped running. He officially filed for re-election on January 20, 2017, the day of his inauguration, and held his first 2020 rally in February, 2017, in nearby Melbourne, Florida.

He has continued holding his signature "Make America Great Again" rallies in the months since, while also raising millions to fund a more professional, far larger campaign operation, with about 80 staffers now working at the campaign's Virginia headquarters, in New York and in key states across the country.

Despite his perch in the White House, Trump is hoping to replicate the dynamics that allowed him to capture the Republican Party and then the presidency in 2016 as an insurgent intent on disrupting the status quo.

But any president is inherently an insider. Trump has worked in the White House for two-and-a-half years, travels the skies in Air Force One and changes the course of history with the stroke of a pen or the post of a tweet.

"We're taking on the failed political establishment and restoring government of, by and for the people," Trump said in a video released by his campaign Monday.

That populist clarion was a central theme of his maiden political adventure, as the businessman-turned-candidate successfully appealed to disaffected voters who felt left behind by economic dislocation and demographic shifts. And he has no intention of abandoning it, even if he is the face of the institutions he looks to disrupt.

He underscored that on the eve of the rally in the must-win swing state of Florida, returning to the hard-line immigration themes of his first campaign by tweeting that, next week, Immigration and Customs Enforcement "will begin the process of removing the millions of illegal aliens who have illicitly found their way into the United States." That promise, which came with no details and sparked Democratic condemnation, seemed to offer a peek into a campaign that will largely be fought along the same lines as his first bid, with very few new policy proposals for a second term.

Early Democratic front-runner Joe Biden said Tuesday that Trump's politics are "all about dividing us" in ways that are "dangerous - truly, truly dangerous."

His deputy campaign manager Kate Bedingfield added in a statement that the country "cannot afford four more years of Trump."

But those involved in the president's reelection effort believe that his brash version of populism, combined with his mantra to "Drain the Swamp," still resonates, despite his administration's cozy ties with lobbyists and corporations and the Trump family's apparent efforts to profit off the presidency.

Advisers believe that, in an age of extreme polarization, many Trump backers view their support for the president as part of their identity, one not easily shaken. They point to his seemingly unmovable support with his base supporters as evidence that, despite more than two years in office, he is still viewed the same way he was as a candidate: the bomb-throwing political rebel.

Trump and those who spoke before him also tried to make the case that Trump had made good on his 2016 promises, including cracking down on illegal immigration and boosting jobs.

"He said he'd make America great again and that's exactly what we've done," said Pence in his introduction.

On Monday, a boisterous crowd of thousands of Trump supporters, many of them in red hats, began gathering outside the Amway Center arena in Orlando, where the campaign had organized a festival with live music and food trucks.

They spent Tuesday braving downpours and listening to a cover band playing Southern rock standards such as Lynyrd Skynyrd's "Sweet Home Alabama" at an outdoor "45 Fest" the campaign organized to energize the crowd. Vendors sold water, as well as pins, hats and T-shirts with slogans including "Trump 2020" and "ICE ICE Baby," a reference to the law enforcement agency tasked with enforcing immigration laws. In the high-80s heat, some women wore "Make American Great Again" bathing suits.

"Trump has been the best president we've ever had," said Ron Freitas, a retired Merchant Marine and registered Democrat from the Orlando area who sat in a lawn chair. Freitas said he was sure Trump would prevail over whomever his Democratic opponent was.

Alex Fuentes, a municipal diesel mechanic, wore a shirt that said "Make Democrats cry again." He said he was an Iraq veteran who twice voted for Barack Obama but parted company with Democrats such as Hillary Clinton, mostly over foreign policy.

"There's a lot of minorities that are hidden Trump supporters," Fuentes said.

Close by, hundreds of anti-Trump protesters clapped and took photos when a 20-foot (6-meter) blimp of a snarling Trump baby in a diaper was inflated. The blimp looks like the one that flew in London during Trump's recent state visit but is not the same one.

"The goal is to get under his skin," said Mark Offerman, the blimp's handler.

Protester Shaun Noble wore a rainbow-colored sign that said "Super, Callous, Fragile, Racist, Sexist, Nazi, POTUS."

Noble's mother was at the Trump rally while he was at the anti-Trump protest.

"It's really caused a divide in our relationship," Noble said. "But it's my right to believe what I want to believe in, and it's her right to believe what she wants to believe."

Some members of the far-right hate group Proud Boys were spotted marching in Orlando and at least twice tried to enter the street where the anti-Trump protest was being held. They were stopped by groups of police officers and deputies. As they walked away, a man from the Proud Boys group said, "We're just Americans. This is a sad day."