CHICAGO: White House hopefuls Kamala Harris and Donald Trump set out Friday on the final 10-week sprint to election day, with the vice president surging after an electrifying speech accepting the presidential nomination.

Less than three weeks before the US vice president and the Republican ex-president meet to debate — and only a month before early in-person voting begins — polls show the race is neck and neck.

Harris, a former senator and California prosecutor, leaves Chicago with momentum, having out raised Trump and erased the polling leads he enjoyed before she replaced President Joe Biden on the Democratic ticket last month.

A new twist in the contest could come with the expected announcement by third party candidate Robert F Kennedy Jr that he is dropping out — and also possibly endorsing Trump.

Kennedy, a conspiracy theorist who has been shunned by much of his famous family, has little support, but even a sliver of extra voters on Trump's side could turn an election likely to be decided by minuscule margins.

Harris accepted her party's presidential nomination Thursday on a glitzy final night in Chicago to set the stage for the gruelling run-in to November 5.

In just a month, Harris, the first black woman to top a major party ticket, has raised a record-breaking half a billion dollars, enjoying a political honeymoon that shows little sign of ending.

Kennedy withdrawal

Potential headwinds for Harris include internal party tensions over US policy on Israel's tyranny over Palestinians in Gaza and fallout from Kennedy dropping out.

The controversial scion of America's revered Kennedy clan is planning an announcement in Arizona, while Trump is also campaigning in the state and promising to showcase a "special guest."

Kennedy's running-mate, Nicole Shanahan, claimed on X that Democrats were "flooding" her with "frantic calls, texts and emails" and were "terrified of the idea of our movement joining forces with Donald Trump."

But analysts are mixed on the effect a Kennedy exit would have.

Democratic heavy hitters, from Michelle Obama and Bill Clinton to vice presidential nominee Tim Walz, have warned that the party could still lose to Trump's Republicans if complacency creeps in.

"If we see a bad poll — and we will — we've got to put down that phone and do something," the former first lady told the party faithful in Chicago.