Making history: Clinton secures presidential nomination
Obama to take aim at Trump after First Lady wows convention and helps to unite Democrats
Barack Obama is set to launch a scathing attack on Donald Trump - calling the billionaire dangerous and unqualified - as he seeks to smooth Hillary Clinton's path to the White House.
In an address to the Democratic National Convention in Philadelphia today, Mr Obama is also expected to make an appeal for the party faithful and undecided voters alike to unite behind Mrs Clinton, presenting her as the only candidate who could further the accomplishments of his presidency.
Mr Obama is due to praise Mrs Clinton's "judgment, skill and leadership", advisers said.
It comes as some supporters of Bernie Sanders, her left-wing rival for the Democratic nomination, vowed to continue their "revolution", turning the event into a rebellion and refusing to vote.
Mr Obama's appearance will be the second time he has taken the stage in recent weeks in a major campaigning effort for Mrs Clinton.
It follows an address by Michelle Obama, delivered on the opening night of the four-day convention, that was heralded as the most electrifying speech of the US election race so far.
The Obamas are not known for having a strong friendship with the Clintons - the couples rarely spend time together - and Mr Obama is said to have found former president Bill Clinton's company irritating.
But the passion with which they are now campaigning together reflects the high stakes in the election.
Taking the stage in a bluebell-coloured dress, Mrs Obama's voice cracked with emotion as she said: "This election and every election is about who will have the power to shape our children for the next four or eight years of their lives."
Many in attendance were moved to tears as Mrs Obama spoke, her voice breaking with emotion. "The story of generations of people who have felt the lash of bondage, the shame of servitude, the sting of segregation but who kept on striving and doing what needed to be done so that today I wake up every morning in a house that was built by slaves and I watch my daughters, two beautiful, intelligent black young women, playing with their dogs on the White House lawn," she said.
"And because of Hillary Clinton, my daughters, and all our sons and daughters, now take for granted that a woman can be president of the United States."
The Obamas were part of a high-profile cast appearing at the convention to draw the party together after a bitter and close-run primary election.
Mr Sanders has energised independents and parts of the Democratic Party who were long disillusioned with conventional politics, attacking Wall Street and promising a higher minimum wage.
In the early hours of the convention, it seemed there would be a full-scale revolt. Thousands of his supporters chanted his name, waved signs, and booed until they drowned out speakers. Mr Sanders tried to quell the rebellion but was booed by his own followers when he said Mrs Clinton would make an "outstanding president".
An array of office holders and celebrities hammered home the call for unity, with singer Paul Simon performing his song 'Bridge Over Troubled Water' as delegates linked arms and swayed to the music.
Former President Bill Clinton smiled and clapped from the audience. Bitterness also lingered over the leak of 19,000 emails showing party insiders had sought to undermine Mr Sanders during the primary campaign.
Democratic officials claimed the emails had been hacked by Russian intelligence agencies intent on helping Mr Trump.
A spokesman for Vladimir Putin accused US politicians of being "paranoid".
US secretary of state John Kerry raised the issue with Russian foreign minister Sergey Lavrov at a meeting in Laos.
Mr Lavrov denied the allegations, saying: "I don't want to use four-letter words."
Mr Clinton was due to address the convention last night and was expected to highlight lesser known aspects of his wife's early life in an attempt to paint her as a more sympathetic character.
The Clinton campaign made a fundraising appeal in which it suggested the presidential race was tied. It said: "Poll after poll is showing that Trump has been eating away at our lead." © The Daily Telegraph, London)