Donald Trump on Tuesday is celebrating the first 100 days of what is already one of the most radical and far-reaching presidencies in US history, as polls show Americans are becoming disenchanted with the economic and political tumult.

The 47th president will mark the milestone in trademark style, seeking to rejuvenate his base with a rally in the battleground state of Michigan that swung his way in November as he soundly defeated Kamala Harris.

Trump has shaken up the United States like few presidents before him. 

His billionaire backer Elon Musk has led the decimation of the federal workforce, and the president himself has reshaped relations with the world by slapping sweeping tariffs, berating allies and eliminating the vast majority of foreign aid.

Polls show Trump has quickly seen the honeymoon that Americans historically accord presidents at the start of their terms evaporate.

A poll published Sunday by The Washington Post and ABC News found that only 39 percent of Americans approve of Trump's performance.

The survey showed net disapproval even on what was his most popular issue -- his aggressive crackdown on immigration -- as controversy swirls over deportations without due process.

Trump angrily dismissed the polls, writing on his Truth Social platform that they are "fake" and saying: "We are doing GREAT, better than ever before."

But even famously defiant Trump has been tacitly acknowledging that he must moderate some policies as stock market turmoil takes a toll.

Wall Street, down more than six percent since Trump took office, ticked up Tuesday on news he would soften some of the sweeping tariffs impacting automakers.

He also recently backtracked on threats to fire Federal Reserve Chairman Jerome Powell, who has warned that Trump's tariffs would likely reignite inflation.

'Having a lot of fun'

After a 2017-2021 term in which some aides sought to rein him in, Trump has surrounded himself this time with unabashed loyalists.

Defense Secretary Pete Hegseth marked the 100 days with a video promoting a collectible miniature of Mount Rushmore in which Trump's likeness has been added to presidential greats.

"The first time, I had two things to do -- run the country and survive; I had all these crooked guys," Trump said in an interview with The Atlantic magazine.

"And the second time, I run the country and the world," he said, adding "I'm having a lot of fun."

Trump since 20 January has also unleashed political revenge.

In the grand entrance hallway of the White House, he has moved a portrait of Barack Obama, the United States' first Black president, to make way for a painting of himself surviving an assassination attempt.

He has used threats of cutting off government access and contracts to pressure law firms whose partners once were involved in cases against him, and he has frozen billions of dollars in funding for universities -- hotbeds of criticism against the administration.

Stretching limits

Unlike most presidents, Trump has focused more on energizing his base than broadening his appeal -- and many supporters are still with him.

Frank Tuoti, a 72-year-old retired machinist from New Hampshire, said: "So far, I'm very satisfied with the job he's doing." 

But he concedes that the tariff instability has made him "a little concerned about the economy."

The rival Democratic Party has seized on economic anxieties although it has also struggled in polling.

"Trump is to blame for the fact that life is more expensive, it's harder to retire, and a 'Trump recession' is at our doorstep," the Democratic National Committee said, calling the 100 days a "colossal failure."

Even with Congress narrowly in Republican hands, Trump has tested the limits of presidential power by signing more than 140 executive orders, many of which have faced court scrutiny.

Trump has sought to end birthright citizenship -- which is guaranteed by the US Constitution -- and Musk has summarily axed billions of dollars appropriated by Congress.

Trump has shown signs of impatience. He promised on the campaign trail to end the Ukraine war within 24 hours, but Russia has rebuffed a broad ceasefire offer.

Reminded of his promise to end the war on "day one" in an interview with Time magazine, the former reality TV star responded: "Obviously, people know that when I said that, it was said in jest."