Democrats are gathering in Chicago to celebrate Vice-President Kamala Harris's campaign for the White House against Republican Donald Trump and to honour President Joe Biden, whose exit from the race turned his party's fortunes around.
Monday's kick-off of the four-day Democratic National Convention is expected also to draw tens of thousands of protesters, many of them opposed to the Biden administration's support for Israel's Gaza offensive, who will march on a route through the city outside the security perimeter.
Biden, 81, who reluctantly ended his re-election campaign a month ago under pressure from top Democrats worried he was too old to win or govern for another four years, will give a prime-time address at the convention on Monday night to make the case for electing Harris and defeating former president Trump, 78.
As Democrats seek to project a sense of unity after the unprecedented change-up in candidates, Harris, 59, is likely to join Biden on stage, where he will ceremonially pass the torch to her.
Harris will formally accept the nomination on Thursday night with a highly anticipated speech.
If elected on November 5, Harris would make US history as the first female president.
A coalition of some 200 social justice organisations, many from pro-Palestinian groups, will gather outside the convention.
Some pro-Palestinian delegates to the convention are pushing for the party to change its platform to limit weapons to Israel.
Harris is heading into the convention riding a historic whirlwind: her campaign has broken records for fundraising, packed arenas with supporters, and turned opinion polls in some battleground states in Democrats' favour.
Biden abandoned his re-election bid after his disastrous debate against Trump on June 27 prompted longtime allies, major donors and other party supporters to demand he step aside.
Polls a month ago showed Trump with a clear lead over Biden, but Harris has closed the gap both nationally and in many of the highly competitive states including Pennsylvania that will play a decisive role in the election.
"I've been to every convention since I was able to vote, and I can say I’ve not felt this kind of energy and electricity at any convention other than the one for Barack Obama," said Democratic Illinois Governor JB Pritzker on CNN's State of the Union on Sunday.
Harris went on a bus tour in western Pennsylvania on Sunday with her running mate, Minnesota Governor Tim Walz.
During the tour she suggested Trump was a coward whose politics focused on putting down rivals.
She will be in Chicago for much of the week but will make a side trip to Milwaukee on Tuesday for a campaign event, returning to Chicago to hear her husband, Doug Emhoff, address the convention that night.
The Trump campaign will barnstorm the key battleground states to try to steal the spotlight away from Harris and highlight some of the policy issues where Republicans hold a polling advantage.
Trump will deliver remarks on economic policy at a small business in southern Pennsylvania on Monday afternoon before events in North Carolina, Michigan, Arizona and Nevada later in the week.
Some major allies and donors have been urging Trump to steer clear of racial and gender-based insults on Harris and focus his attacks instead on her policy record.
Trump’s Michigan event will be in Howell, a city struggling to move past its racist history, including Ku Klux Klan rallies in the 1970s and 1980s.
In July, about a dozen white supremacists chanted “Heil Hitler” during a march through Howell, while another group of demonstrators shouted “We love Hitler, we love Trump” from a highway overpass in a nearby town.
The Harris campaign criticised Trump for refusing to condemn a "blatant display of racism and anti-Semitism in his name".
A Trump campaign spokeswoman said Trump would emphasise in Howell that hate would have no place in the country if he returned to the White House.
Democrats will also pay tribute on Monday night to their failed 2016 presidential candidate, Hillary Clinton, who is expected to speak before Biden.
Former presidents Barack Obama and Bill Clinton will speak on Tuesday and Wednesday, respectively.
