After $2.1bn spent, 575 days of campaigning and dozens of scandals, finally it comes down to the one day when America will decide its destiny – and it is still too close to call.

It feels like a million years since April 12 2015, when Hillary Clinton let slip the country’s worst kept secret and officially confirmed she was making a second run for the White House.

“Everyday Americans need a champion, and I want to be that champion,” she said in a video published that Sunday afternoon.

In the 18-months since then, she had battled a dogged primary rival, and a rambunctious, aggressive Republican opponent who questioned her stamina, her health and even her legal right to be in the race. Along the way she also suffered various set-backs and blows, many of which were self-inflicted.

Mr Obama said it was essential people turned out to vote (AP)

On a chilly Monday night, Ms Clinton brought her campaign to become America’s first female president to a dramatic, impassioned conclusion as she campaigned in Philadelphia, the city where the US signed Declaration of Independence, at an appearance with President Barack Obama, First Lady Michelle, Ms Clinton's husband Bill Clinton, her daughter Chelsea, and Bruce Springsteen and Jon Bon Jovi.

“Please go out and vote tomorrow,” urged Springsteen, who performed Thunder Road and Dancing the Dark to an adoring crowd.

Ms Clinton had gone into the final day of campaigning with a majority of polls giving her a small but solid lead over Mr Trump. A final tracking poll by the Washington Post-ABC News scored it 47 per cent to 43 per cent. Meanwhile, final poll by CBS News gave Ms Clinton a lead of four points, scoring it 45 per cent to 41 per cent. Very few people interviewed said they were likely to change their minds.

“This country began here,” said Bill Clinton, to roars from the estimated 20,000 people present. He said that his wife had campaigned with a message about how the country could move forward. “We are better together,” he said.

Mr Clinton was followed by Michelle Obama, who has has emerged as one of Ms Clinton’s most effective campaigners. She said the country deserved a leader who “respects our daughters” and “recognises the dignity in all of us’.

US Election: Hillary Clinton in profile

“If we get out tomorrow, Hillary Clinton will win,” she said.

Next it was the turn of Barack Obama who spoke for 20 minutes. He said it had been a “long campaign with a lot of distraction”. “Donald Trump is uniquely unqualified to be our chief executive,” he said. “Hillary is respected around the world.”

Mr Obama’s voice soared. “I’m asking you to vote for this woman, this mother, this grandmother, to be the next president of the United States.

After all of that, it would be have a tough act for anyone to take to the stage. But Ms Clinton, while not in the league of Mr Obama or the First Lady, or indeed her husband, has greatly improved as a candidate and campaigner since that April day when she announced her run.

Ms Clinton was joined by her husband and daughter, and the president and the first lady (AP)

“Thanks for coming out for one last rally before election day tomorrow. I am personally so happy to be finishing this campaign with my husband and my daughter by my side," she said.

“We’ve been traveling across the country to try and meet as many people as possible but it's great to have them by my side tonight.”

She added: “I believe our best days are ahead of us if we reach for them.”

The evening had begun with Jon Bon Jovi, who said he had known the candidate for 20 years, and that she had suffered the blows of a lifetime in service, but that she had also accumulated the knowledge. “I am voting for someone who sees my nieces as future leaders, and not objects to be rated,” said Bon Jovi, who completed his set with a version of The Beatles Here Comes the Sun.

Both Bruce Springsteen and Jon Bon Jovi performed (AP)

Watching all of it was Brian Patterson, a 23-year-old student from Connecticut said he had to see Ms Clinton because he wanted to help create a country where people could live with dignity. Mr Patterson, who was African American, said the country was at a turning point. Things could either go well, or else go badly. “We can’t let him get in,” he said of Mr Trump.

Peter Abuto, a lawyer, said Ms Clinton was extremely well qualified for the presidency, as much as anyone who had run before. But he admitted he was also motivated by his anguish about Mr Trump.

He said: “Everything about is anathema to the idea of America.”

Mr Trump himself, who began his own journey to seek the White House in June 2015 when he appeared on the escalators at Trump Tower to insult Mexicans, drew his own frantaic campaign to a halt as well.

The Associated Press said he channelled Hollywood at the final rally of his unconventional presidential campaign.