WASHINGTON (AP) — It's the election that no one could have foreseen.

Not so long ago, Donald Trump was marinating in anger at Mar-a-Lago after being impeached twice and voted out of the White House. Even some of his closest allies were looking forward to a future without the charismatic yet erratic billionaire leading the Republican Party, especially after his failed attempt to overturn an election ended in violence and shame. When Trump announced his comeback bid two years ago, the New York Post buried the article on page 26.

At the same time, Kamala Harris was languishing as a low-profile sidekick to President Joe Biden. Once seen as a rising star in the Democratic Party, she struggled with both her profile and her portfolio, disappointing her supporters and delighting her critics. No one was talking about Harris running for the top job — they were wondering if Biden should replace her as his running mate when he sought a second term.

But on Tuesday, improbable as it may have seemed before, Americans will choose either Trump or Harris to serve as the next president. It's the final chapter in one of the most bewildering, unpredictable and consequential sagas in political history. For once, the word "unprecedented" has not been overused.

"If someone had told you ahead of time what was going to happen in this election, and you tried to sell it as a book, no one would believe it," said Neil Newhouse, a Republican pollster with more than four decades of experience. "It's energized the country and it's polarized the country. And all we can hope is that we come out of it better in the end."

History was and will be made. The United States has never elected a president who has been convicted of a crime. Trump survived not one but two assassination attempts. Biden dropped out in the middle of an election year and Harris could become the first female president. Fundamental tenets about democracy in the most powerful nation on earth will be tested like no time since the Civil War.

And that's not to mention the backdrop of simultaneous conflicts in Europe and the Middle East, hacking by foreign governments, an increasingly normalized blizzard of misinformation and the intimate involvement of the world's richest man, Elon Musk.

For now, the only thing the country can agree on is that no one knows how the story will end.

Trump rebounded from disgrace to the Republican nomination

Republicans could have been finished with Trump after Jan. 6, 2021.

That's the day he fired up his supporters with false claims of voter fraud, directed them to march on the U.S. Capitol while Congress was ceremonially certifying Biden's election victory, and then stood by as rioting threatened lawmakers and his own vice president.

But not enough Republicans joined with Democrats to convict Trump in an impeachment trial, clearing a path for him to run for office again.

Trump started planning a comeback even as some leaders in his party hoped he would be eclipsed by Ron DeSantis, the Florida governor, or Nikki Haley, the former South Carolina governor who served as Trump's ambassador to the United Nations.

In the year after Trump announced that he would run against Biden, he faced criminal charges four times. Two of the indictments were connected to his attempts to overturn his election defeat. Another involved his refusal to return classified documents to the federal government after leaving office. Trump has pleaded not guilty to all the charges, and none of those cases have been resolved.

However, a fourth indictment in New York led to Trump becoming the first president in U.S. history to be criminally convicted. A jury found him guilty on May 30 of falsifying business records over hush money payments to a porn star who claimed they had an affair.

None of it slowed Trump, who practically ignored his opponents during the primary as he barreled toward the Republican presidential nomination. A mugshot from one of his arrests was adopted by his followers as a symbol of resisting a corrupt system.

Trump's candidacy capitalized on anger over inflation and frustration about migrants crossing the southern border. He also hammered Biden as too old for the job even though he's only four years younger than the president.

But Democrats also thought Biden, 81, would be better off considering retirement than a second term. So when Biden struggled through a presidential debate on June 27 — losing his train of thought, appearing confused, stammering through answers — he faced escalating pressure within his party to drop out of the race.

As Biden faced a political crisis, Trump went to an outdoor rally in Butler, Pennsylvania on July 13. A young man evaded police, climbed to the top of a nearby building and fired several shots with a semiautomatic rifle.

Trump grabbed at his ear and dropped to the stage. While Secret Service agents crowded around him, he lurched to his feet with a streak of blood across his face, thrust his fist in the air and shouted "fight, fight, fight!" An American flag billowed overhead.

It was an instantly iconic moment. Trump's path to the White House seemed clearer than ever — perhaps even inevitable.

Harris gets an unexpected opportunity at redemption

The vice president was getting ready to do a puzzle with her nieces on the morning of July 21 when Biden called. He had decided to end his reelection bid and endorse Harris as his replacement.

She spent the rest of the day making dozens of phone calls to line up support, and she had enough to secure the nomination within two days.

It was a startling reversal of fortune. Harris had flamed out when running for president four years earlier, dropping out before the first Democratic primary contest. Biden resuscitated her political career by choosing her as his running mate, and she became the first woman, Black person and person of South Asian descent to serve as vice president.

But Harris' struggles did not end there. She fumbled questions about immigration, oversaw widespread turnover in her office and faded into the background rather than use her historic status as a platform.

All of that started to change on June 24, 2022, when the U.S. Supreme Court overturned the nationwide right to abortion enshrined by Roe v. Wade. Harris became the White House's top advocate on an issue that reshaped American politics.

She also proved to be more nimble than before. Shortly after returning from a weeklong trip to Africa, her team orchestrated a spur-of-the-moment venture to Nashville so Harris could show support for two Tennessee lawmakers who had been expelled for protesting for gun control.

Meanwhile, Harris was networking with local politicians, business leaders and cultural figures to gain ideas and build connections. When Biden dropped out, she was better positioned than many realized to seize the moment.

The day after she became the candidate, Harris jetted to Wilmington, Delaware to visit campaign headquarters. Staff members had spent the morning printing "Kamala" and "Harris for President" signs to tape up next to obsolete "Biden-Harris" posters.

There were 106 days until the end of the election.

The battle between Trump and Harris will reshape the country

While speaking to campaign staff in Wilmington, Harris used a line that has become a mantra, chanted by supporters at rallies across the country. "We are not going back," she declared.

It's a fitting counterpoint to Trump's slogan, "make America great again," which he has wielded since launching his first campaign more than eight years ago.

The two candidates have almost nothing in common, something that was on display on Sept. 10, when Harris and Trump met for the first time for their only televised debate.

Harris promised to restore abortion rights and use tax breaks to support small businesses and families. She said she would "be a president for all Americans."

Trump took credit for nominating the justices that helped overturn Roe, pledged to protect the U.S. economy with tariffs and made false claims about migrants eating people's pets. He called Harris "the worst vice president in the history of our country."

Harris was widely viewed as gaining the upper hand. Trump insisted he won but refused a second debate. The race remained remarkably close.

Pundits and pollsters have spent the final weeks straining to identify any shift in the candidates' chances. Microscopic changes in public opinion could swing the outcome of the election. It might take days to count enough votes to determine who wins.

The outcome, whenever it becomes clear, could be just another surprise in a campaign that's been full of them.