19:56

Barack Obama today made his most aggressive foray yet into the battle to succeed him, warning that Donald Trump would serve the interests of his fellow billionaires and heighten the risk of another financial crisis.

Barack Obama Photograph: Scott Olson/Getty Images

Returning to Elkhart, Indiana, the first city he visited as president, Obama defended his economic record over the past seven years against not only Republicans but “talking heads” who theorise that outsiders Trump and Bernie Sanders have thrived because of bad trade deals that hollowed out communities.

The president stood at a podium jacketless, with his sleeves rolled up, apparently relishing a return to election campaign mode even though he is not on the ballot. He did not mention Trump or Hillary Clinton by name but displayed how he is likely to be a formidable weapon for his fellow Democrat during the general election.

“The one thing I can promise you is if we turn against each other based on divisions of race or religion, if we fall for a bunch of okey doke just because it sounds funny or the tweets are provocative, then we’re not going to build on the progress that we’ve started,” he said to applause and cheers from 2,000 people in a brightly lit gymnasium. “If we get cynical and just vote our fears, or if we don’t vote at all, we won’t build on the progress that we’ve started.”