Barack Obama headlines DNC, Republicans endorse Harris

Former US President Barack Obama returns to the national stage on Tuesday night to boost his longtime Democratic ally Kamala Harris in her 11th-hour presidential bid against Republican Donald Trump.

America's first Black president, Obama has thrown his considerable political capital behind Harris as she seeks to make history herself on Nov. 5 as the first woman and first Black and South Asian person to be elected US president. 

Obama will be preceded by his wife Michelle, who tops Democrats' wish list as a future president. 

Republicans who have left the fold since Trump's takeover of their party crossed the aisle on Tuesday night to address the convention, including Trump's former White House press secretary Stephanie Grisham and former Trump voter Kyle Sweetser. 

Later in the evening, Republican Mayor John Giles of Mesa, Arizona, was due to speak. 

Grisham described her journey from a Trump "true believer" to the first senior White House staffer to resign after the Jan. 6, 2021, attack by Trump supporters on the US Capitol.

"He has no empathy, no morals and no fidelity to the truth," she said. "Kamala Harris tells the truth. She respects the American people. And she has my vote." 

Conservative voters who dislike Trump have been one of the Democrats' hoped-for prizes. The challenge will be persuading them to get to the ballot box in November and vote for Harris, versus staying home or writing in a presidential candidate.

Harris' fledgling campaign, still light on policy specifics, has coasted on the enthusiasm of Democrats relieved by the departure of Joe Biden, a beloved 81-year-old president who had become a liability.

Obama will outline what he believes will lift Harris to victory while also warning Democrats about the tough task they face over the next 11 weeks, according to a source familiar with the remarks. The former first lady will emphasise the need for the country to turn the page on fear and division. 

US Senator Bernie Sanders will speak along with Senate Democratic Leader Chuck Schumer, Illinois Governor JB Pritzker and Douglas Emhoff, Harris' husband. 

Trump and his vice presidential running mate, JD Vance, are barnstorming battleground states this week in a bid to steer attention away from the convention in Chicago and highlight Trump's policy differences with Harris.

At a campaign stop in Howell, Michigan, Trump repeated  unsupported claims that Harris took a permissive approach to law enforcement.

"You can't walk across the street to get a loaf of bread. You get shot, you get mugged, you get raped," he said.

Trump spoke one month after white supremacists rallied in the small town. Trump himself has made racist remarks about Harris.

Harris and her vice presidential pick, Minnesota Governor Tim Walz, travelled to Milwaukee on Tuesday for a campaign rally in the same venue as last month's Republican National Convention, where Trump formally received his party's nod. 

Her remarks will be livestreamed into Chicago's United Center, a basketball and hockey arena and site of the convention.

THE OBAMA IMPACT 

At 63, Obama looms large in moments of crisis, including during the messy deliberations that led Biden to step out of the race last month and endorse his vice president.

Along with former House Speaker Nancy Pelosi, he is viewed by some as having been a driving force behind the party revolt. 

Biden took centre stage on Monday, the assembly's opening night, drawing an extended standing ovation from the party faithful and delivering a speech that stretched well past midnight.

Like his successors, Obama presided over a closely divided country during his two terms from 2007-2017. But his healthy electoral margins in 2008 and 2012 are now considered out of reach for Harris.

Trump launched his political career through racist attacks on Obama's citizenship status and then succeeded him in the White House, a bitter legacy for liberals that Obama may reflect upon when he speaks.