Barack Obama has endorsed Joe Biden for president, casting his former vice-president as the experienced statesman and unifying leader that will be needed to confront the public health and economic crisis caused by the coronavirus pandemic that will probably be the defining issue of the 2020 presidential election. Obama’s endorsement, a 12-minute video published on Tuesday, came just one day after Biden’s one-time rival Bernie Sanders threw his weight behind him and appealed to progressives to unify against Donald Trump. Ahead of what is certain to be a historically divisive general election fight, the former president called for “Americans of all political stripes” to come together in a “great awakening” behind the presumptive Democratic nominee. “Joe has the character and the experience to guide us through one of our darkest times and heal us through a long recovery,” Obama said in his endorsement video. The announcement was Obama’s most extended public commentary on the 2020 election to date. In his remarks, he emphasized Biden’s preparedness to lead the country in this perilous moment, delivered a blistering attack on Republicans, and sought to unify the party in the wake of a fractious primary. “Pandemics have a way of cutting through a lot of noise and spin to remind us of what is real, and what is important,” Obama said. “This crisis has reminded us that government matters. It’s reminded us that good government matters.” The former president remains incredibly popular among Democrats and his active support for Biden could play a key role in energizing and consolidating the party around Biden’s candidacy, which still lacks a spark of enthusiasm even as he racked up a string of commanding primary victories. Obama declined to play a public role in the primary, which Sanders’ departure from the race last week in effect ended, elevating Biden to presumptive nominee. In his remarks, he praised the rivals Biden defeated in the Democratic primary, which he said featured “one of the most impressive Democratic fields ever”. Singling out Sanders, Obama said the Vermont senator was an “American original” who would be critical to defeating Trump in November. When Sanders exited the race, Trump tried to sow discord by questioning why Obama had not yet endorsed Biden. “It does amaze me that President Obama hasn’t supported Sleepy Joe,” the president said during a coronavirus briefing, speculating that his predecessor “knows something that you don’t know, that I think I know, that you don’t know.” In a statement on Tuesday, the Trump campaign suggested Obama was somehow reluctant to support his former vice-president, with whom he shared an uncommon friendship and whom he awarded the presidential medal of freedom in 2017. “Obama has no other choice but to support him,” said Brad Parscale, Trump’s 2020 campaign manager. “Even Bernie Sanders beat him to it.” In 2008, Obama assembled a coalition of African Americans, suburban women, white working-class voters and, crucially, young people in what many Democrats remember as one of the most inspirational campaigns in modern history. Biden has drawn support from similar constituencies but is missing a key part of that coalition: young people, who remain deeply skeptical of his candidacy. To the dismay of some Democrats, Obama has mostly continued the tradition of former presidents by not criticizing his successor, even as Trump has dismantled his legacy on everything from healthcare to climate change. In the midst of a pandemic, Trump has sought to deflect criticism by blaming his predecessor. On Tuesday Obama did not mention his successor by name, instead assailing the party Trump leads and implicitly criticizing him with praise of Biden. “One thing everybody has learned by now is that the Republicans occupying the White House and running the US Senate are not interested in progress,” Obama said. “They’re interested in power.” Biden’s association with Obama helped propel him ahead of younger rivals. His eight years as Obama’s No 2 contributed greatly to his support among African American voters, particularly in South Carolina, the foundation of a remarkable campaign turnaround. His time as vice-president was also central to his argument that he is a capable, experienced leader best positioned to beat Trump in November. Obama made a similar case in his endorsement video, citing Biden’s leadership during the Great Recession, as well as his management of the H1N1 and Ebola crises. Healthcare proved to be a flashpoint during the primary, with candidates divided between expanding the Affordable Care Act, Obama’s signature achievement, or seeking universal health coverage. Biden has resisted Sanders’ Medicare for All plan and advocated for building on the ACA, nicknamed Obamacare. In his video, Obama said it was time to “go further” and ensure that all Americans have access to healthcare, calling on Democrats to push for a public option, expand Medicare and “finish the job so that healthcare isn’t just a right, but a reality for everybody”. Biden, who has pledged to choose a woman for his vice-president, told donors on a fundraising call that Obama advised him to choose someone who is not afraid to disagree with him and who will “always tell me the truth”. “The most important thing – and I’ve actually talked to Barack about this – the most important thing is that there has to be someone who, the day after they’re picked, is prepared to be president of the United States of America if something happened,” Biden said at the virtual fundraiser.