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A cyclist rides past a picture of U.S. President Donald Trump, outside the U.S. Department of the Interior, on the Fourth of July.Nathan Howard/Reuters

When U.S. President Donald Trump took over the celebrations for his country’s 250th birthday, he conceived of them as a combination of world’s fair and MAGA rally that would show off both American power and his efforts to leave a personal stamp on the country’s capital.

But so far, the festivities have been plagued by difficulties. Bands cancelled their performances, attendance has been sparse, algae has tinted the Reflecting Pool green, a mock-up of Mr. Trump’s planned triumphal arch has begun to fall apart and a piece of the main stage came crashing down during rehearsal.

The President will aim to right the ship with Saturday evening’s culminating Salute to America event. Mr. Trump will speak as fighter jets buzz the crowd, followed by a fireworks display billed as the largest in the history of the world.

One complicating factor will be the weather. The U.S. East Coast has baked under a heat dome all week and temperatures in Washington on Saturday are expected to reach 38C with 77 per cent humidity. This has pushed the start time for Mr. Trump’s speech to 9.45 p.m.

Soaring temperatures bear down as Trump gears up to celebrate America 250

Before the evening’s program got underway, however, organizers asked thousands of people to clear the Mall as thunderstorms approached the city. It was not immediately clear how this would affect Mr. Trump’s speech.

The National Guard and Secret Service had turned much of the city centre into a fortress on Saturday afternoon ahead of Mr. Trump’s address. Crowds of celebrants, decked out in a mix of American flag shirts, America 250 apparel and MAGA hats navigated the barriers searching for access points to the fair or patches of shade.

Forrest Lee, 31, in town from Palm Beach Gardens, Fla. had hoped to visit the Vietnam Veterans Memorial but found his path blocked by fencing. He said he understood the security precautions: not only has Mr. Trump survived three assassination attempts, but organizers are bringing in a large amount of fireworks to be shot off from numerous locations, including barges on the Potomac.

“It’s very secure, lots of police, lots of Secret Service. You can barely see the White House. They’re keeping everybody safe, keeping everybody split up. It’s almost intended to keep us from being in one location for security purposes,” he said as he stood with a small crowd along Constitution Avenue, watching flights of helicopters and fighter jets overhead.

Mr. Lee, who owns a classic car rental business not far from Mr. Trump’s Mar-a-Lago estate, is related to Richard Henry Lee and Francis Lightfoot Lee, two signers of the Declaration of Independence, giving added meaning to the celebrations.

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Trump speaks during a rally at Mount Rushmore National Memorial on Friday in Keystone, South Dakota.Chip Somodevilla/Getty Images

The anniversary event arrives as the President’s approval rating has dropped. His war on Iran has seen gas prices rise and, according to a Reuters/Ipsos poll last month, just 23 per cent of Americans believe it has left the country in a stronger position than it had before.

A rolling online tracking poll by Civiqs has his approval rating at 37 per cent and disapproval at 58 per cent, worrying numbers as he seeks to keep Congress under the control of his Republicans this fall.

Mr. Trump delivered what may be a preview of his messaging in a Friday night speech at Mount Rushmore, in which he took aim at recent Democratic Party primary victories by leftist candidates and tried to tie them to his signature issue of immigration.

“There is now a resurgence of the communist menace in our land, including from newcomers who embrace ideas totally opposed to our way of life and our great success,” he said. “Communism is the enemy of free people everywhere, everywhere in the world – never works – it’s the enemy of the constitution, above all, it’s the enemy of July 4, 1776.”

The celebrations, which mark the anniversary of the U.S.’s Declaration of Independence from Great Britain, were originally set to be organized by a bipartisan committee created by Congress.

But the Trump administration set up Freedom 250, which went to work fulfilling Mr. Trump’s campaign promise of a year of festivities, including a Great American State Fair. The event, which features cultural and historical displays from U.S. states and territories, plus a Ferris wheel and rodeo, has been set up on the National Mall for the past week and a half.

Several scheduled musical performers, however, pulled out of the event days after the lineup was announced in May.

As the U.S. turns 250, even the music gatherings are partisan

In an Instagram post, singer Martina McBride said she decided to cancel when she realized it would not be a “non-partisan” event. Added rocker Brett Michaels: “Unfortunately, what was presented to us as a celebration of our country has evolved into something much more divisive.”

The Commodores, Morris Day and the Time, Young MC, and Milli Vanilli also decided to call off their performances.

In their stead, Mr. Trump replaced a planned kickoff event last week with a rally hosted by himself.

At least 10 states, including Illinois, Pennsylvania, Massachusetts and Oregon, chose not to participate in the fair. Some, such as Illinois and Massachusetts, cited cost as the reason. The Oregon governor’s office also said it did not want to take part in a “partisan affair.”

At Opinion: At 250 years old, America is barely recognizable

Amid the extreme heat, attendance at the fair has also appeared to be low. Viral photos and videos show only a trickle of people amid acres of green grass on the Mall and, in one case, a musical performance taking place in front of just 10 audience members.

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Attendees exit the grounds of the Great American State Fair after the event was closed for the afternoon due to extreme heat on the National Mall on Friday.Nathan Howard/The Associated Press

Earlier this week, Mr. Trump insisted on social media that the fair was “packed with happy people” who were “loving it.”

“Ask yourself this simple question, ‘DO YOU THINK THAT OBUMA OR SLEEPY JOE BIDEN COULD HAVE DONE IT?’ THE ANSWER IS NO!” he wrote.

Greg and Denise Gorlich, who travelled from St. Charles, Ill., for the festivities with their son, pronounced themselves among the impressed. “It’s just been a wonderful couple of days,” said Mr. Gorlich, 64. “This would not have happened without President Trump. No one else could have pulled this off.”

Ms. Gorlich, 65, named the Florida pavilion as a state fair highlight: the Sunshine State’s display features a putting green, the scent of an orange grove and free manatee stuffies.

“The only disappointment is that not all the states were represented,” she said.

Jayna Wells, a 53-year-old teacher, said the fair was “a nice idea but poor execution.” There is only one access point for much of downtown, leaving crowds wandering the fence line looking for a way in. And she disagreed with the political bent: one religious pavilion exclusively features several conservative evangelical groups.

“It’s not overly well-attended or well-organized. The access is making it harder for people to participate,” she said. “And it’s too political.”

To push back on the celebrations’ pro-Trump bent, Ms. Wells dressed as the Statue of Liberty and carried a white board in her hand that read “liberty for all, including women, transgender people and immigrants.”

“I dressed as Lady Liberty because I believe our constitution should have liberty for everyone,” she said. “The statue is near Ellis Island, where so many people came in. And now, there’s this angst towards people coming to our country.”

Overlooking Ms. Wells as she spoke was a large banner of Mr. Trump’s face, recently hung from the front of the Department of the Interior. It joins similar banners showing the President that hang from the departments of Justice and Labour.

The fair was also at least partly intended to show off Mr. Trump’s efforts to beautify Washington and give it his imprimatur, which have included cleaning up city parks and its central train station. To that end, organisers erected a plywood and plastic mock-up of a triumphal arch that Mr. Trump plans to have built across the Potomac River from the Lincoln Memorial.

The vinyl wrap on the model, however, has begun to wrinkle and warp, while its upper portions have developed cracks, which appear to have been plugged with yellow spray foam.

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Tall ships parade under flyovers during the International Parade of Sail, part of Sail250, a gathering of tall ships and military ships, on Saturday in New York.Seth Wenig/The Associated Press

On Thursday, meanwhile, video posted online by independent journalist Aaron Parnas showed a piece of the stage falling from the rigging with a crash behind a group of dancers rehearsing. Freedom 250 said that the incident, which appeared to come close to striking some of the dancers, resulted from work taking place behind the scenes. It said no one was hurt.

Another source of trouble has been the Reflecting Pool, which Mr. Trump ordered drained, covered with a new liner in “American flag blue,” and fitted with a new filtration system. The President at one point had his motorcade drive through the empty pool to inspect the work.

Within days of being refilled, however, the pool had grown a large green algae bloom and pieces of the liner had come unstuck from the bottom. After trying to deal with the problem by pouring bottles of hydrogen peroxide into the water, authorities had the pool – which had attracted both anti-Trump protestors and curious onlookers – fenced off.

Mr. Trump has claimed without evidence that people have deliberately cut the liner up with boxcutters. Several people were arrested after allegedly touching the liner.

One, a 67-year-old former Olympic canoeist named David Hearn, was indicted this week for “destruction of property.” Mr. Hearn has said he merely reached into the pool to touch a piece of lining that was already floating in the water.