Barack Obama headlines DNC on Tuesday, will campaign for Harris

Chicago: Former US President Barack Obama will endorse the presidential bid of his longtime political ally Kamala Harris on Tuesday night in a high-profile speech aimed at boosting her new and untested presidential bid.

At 63, Obama is keen to influence his party behind the scenes and maintains a legacy and a voice that loom large in moments of crisis, including during the messy deliberations that ultimately led President Joe Biden to step out of the race and endorse Harris, 59.

Nearly eight years after the end of his presidency, Obama remains one of the most popular Democrats in the country, eclipsing Harris and the current administration, public opinion polls show.

In a prime-time address to the Democratic National Convention on Tuesday, the first Black US president lends his own star power to a campaign, light on policy specifics, that has to date coasted on joyful vibes and the relief of Democrats delighted that Biden's flailing campaign is over.

Biden took center stage on Monday, the convention's opening night, drawing an extended standing ovation from the party faithful and, even with five months left in office, delivering a farewell speech to the party he has served for half a century.

Like his successors, Obama presided over a closely divided country. But his victories were enviable by today's standards for a Democrat: he won in 2008 and 2012 by healthy Electoral College margins, carrying not just Michigan, Pennsylvania and Wisconsin, but also Florida, Iowa and Ohio, states now considered out of reach for Harris and running mate Tim Walz.

But his presidency also fueled the rise of Republican Donald Trump as a titanic right-wing figure, a bitter legacy for liberals that he may reflect upon in his speech.

In his speech, 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.

A tight race

Harris and Trump are locked in a tight presidential race that will likely be decided in a handful of battleground states, polls show.

"President Obama believes this is an all-hands-on-deck moment, and is committed to doing all he can to elect Vice President Harris and Democrats across the country," said Eric Schultz, an Obama adviser.

Obama will make appearances in coming weeks where he believes he can help move the needle and persuade voters, especially in the battleground states likely to decide the election, Schultz said.

Former first lady Michelle Obama is also expected address the convention, emphasizing the need for the country to turn the page on fear and division, according to a source familiar with her plans.

In 2016, she offered a memorable catchphrase of "When they go low, we go high" in a speech supporting Hilary Clinton's presidential campaign. Clinton spoke at the convention on Monday.

Michelle Obama's name has often been tossed around as a dream presidential candidate for Democrats; to their dismay, she has shown no interest in electoral politics.

A Reuters/Ipsos poll early this month showed that 55% per cent of Americans - and 94 per cent of Democrats - viewed Michelle Obama favorably, higher approval than Harris' 37 per cent nationally and 81 per cent within the party.

Tuesday’s convention theme, "A Bold Vision for America’s Future," will include a ceremonial roll call vote from the 57 different state and territory delegations.

Harris and Walz will travel to Milwaukee on Tuesday to attend a campaign rally. It will be Harris’s seventh visit to Wisconsin this year and her third since becoming the Democratic presidential candidate.

Harris's remarks will be livestreamed into Chicago's United Center, the site of the convention.