[WASHINGTON] President Barack Obama will campaign with presumptive Democratic White House nominee Hillary Clinton for the first time next Tuesday, as a new poll shows a tightening race with Republican Donald Trump.
The Democratic pair is scheduled to visit Charlotte, in the swing state of North Carolina, where they will "discuss building on the progress we've made and their vision for an America that is stronger together," Mrs Clinton's campaign said in a statement Wednesday.
Their debut joint campaign appearance for the 2016 election had been scheduled for June 15 in Wisconsin, but was postponed due to the massacre at a gay nightclub in Orlando, Florida - the worst mass shooting in US history.
Mr Obama endorsed Mrs Clinton on June 9 after months of assiduously avoiding tipping the scales of the Democratic presidential primaries.
"I don't think there's ever been someone so qualified to hold this office," Mr Obama said in a video message that day as he offered his full-throated endorsement of the former secretary of state, senator and first lady.
"I'm with her, I am fired up, and I cannot wait to get out there and campaign for Hillary," added Mr Obama, who won a brutal, months-long Democratic primary battle against Mrs Clinton in 2008.
North Carolina is one of about a dozen battleground states where November's election is expected to be decided.
Mr Obama won North Carolina by less than half a percentage point against Republican John McCain in 2008. Four years later, Mr Obama lost it to Mitt Romney by two points.
The joint appearance the day after the July 4 Independence holiday comes with US Senator Bernie Sanders refusing to bow out of the nomination race, despite Mrs Clinton amassing the necessary number of delegates to clinch outright victory at next month's party nominating convention.
But Mrs Clinton has moved on, turning the entirety of her effort towards a bruising showdown with Mr Trump as she aims to become the nation's first female president.
The race is too close to call, with the brash billionaire narrowing the gap with Mrs Clinton, according to the latest Quinnipiac University national poll.
Respondents put Mrs Clinton ahead of Mr Trump just 42 per cent to 40 per cent, a narrowing from Mrs Clinton's four-point margin in the organisation's June 1 survey.
The poll is considerably closer than the 12-point Clinton advantage in Sunday's ABC News/Washington Post poll.
Quinnipiac's survey notably showed that 61 per cent believe the 2016 election "has increased the level of hatred and prejudice" across the country.
Of that group, two thirds blame the Trump campaign, with just 16 per cent blaming Mrs Clinton's team.
Mr Trump has made several incendiary statements during the campaign, including a call for banning Muslims from entering the United States, and describing Mexicans as rapists and criminals.
Meanwhile, respected election data analyst and FiveThirtyEight.com founder Nate Silver, who correctly predicted 50 out of 50 states in the 2012 presidential election, on Wednesday said Mrs Clinton was a 75 or 80 per cent favorite over Mr Trump.
"There's a lot of football left to be played, but she's ahead in almost every poll, every swing state, every national poll," Mr Silver told ABC's "Good Morning America."
Mr Trump's rhetoric has alarmed and angered many in his own party, and there is a longshot conservative movement afoot to deny him the nomination at the party convention in July.
Top Senate Republican Mitch McConnell has endorsed him, but only tepidly, and late Tuesday he acknowledged Mr Trump was not yet a "credible" candidate.
"Trump clearly needs to change, in my opinion, to win the general election," Mr McConnell told Time Warner Cable News.
But Mr Trump was his old contentious self Wednesday, spending several minutes of a rally in Bangor, Maine attacking Republicans whom he had already defeated in the primaries for not honoring their signed pledge to support the party's nominee.
"They should never be allowed to run for public office again because what they did is disgraceful," he boomed.
He also bucked his own party by voicing strong opposition to a stalled trans-Pacific trade deal and saying he wanted to "renegotiate" Nafta, the North American Free Trade Agreement signed by Bill Clinton.