Senator Bernie Sanders on Monday endorsed his longtime rival former Vice-President Joe Biden, a move aimed at unifying a Democratic Party long fractured along moderate and liberal lines ahead of the election match-up against President Donald Trump.

Sanders cited the novel coronavirus outbreak as a reason for the party to come together behind Biden, the likely Democratic presidential nominee after the progressive firebrand Sanders suspended his White House campaign.

Sanders’ endorsement during an online campaign event came as Biden’s team had already begun reaching out to advocacy groups on the left to enlist their support for the November 3 general election battle against the Republican Trump.

Before the pandemic brought the Democratic primary contest to a virtual halt, Biden had built up a commanding delegate edge over Sanders, leading the US senator from Vermont to declare last week he saw no viable path to the nomination.

Even so, it remained unclear how soon Sanders, who is especially popular with liberal young voters, would rally behind Biden, whose support comes chiefly from the party’s older moderates. Sanders’ move to back Biden made for a stark contrast to 2016, when Sanders waited until the eve of the summer Democratic National Convention to support Hillary Clinton.

In the online event, Sanders called on Democrats, independents and Republicans “to come together in this campaign to support (Biden’s) candidacy, which I endorse, to make certain that we defeat somebody who I believe ... is the most dangerous president in the modern history of this country.”

Biden responded by terming Sanders “the most powerful voice for a fair and more just America”.With social distancing in widespread effect, Biden has been forced to move the bulk of his campaign to online events. The Sanders endorsement gives him a much-needed jolt of energy and attention. As the last two standing in a bruising Democratic primary, Biden and Sanders represented the conflict raging within the party. Reuters

between its moderate and liberal wings, with moderates claiming expansive progressive policies would alienate centrist voters needed to beat Trump.

But Biden and Sanders, contemporaries who both have served in the Senate, largely treated each other with civility, even when some on the left wanted Sanders to be more critical of Biden's moderate approach.

”We've disagreed,” Biden said on Monday,“but we've been friends.”

Biden said he and Sanders would develop six policy working groups on issues including the economy, education, criminal justice, immigration and climate change to develop solutions to problems the United States faces.

Trump's re-election campaign used Sanders' endorsement to argue that Biden had moved too far left.

“This is further proof that even though Bernie Sanders won’t be on the ballot in November, his issues will be,” Trump's campaign manager Brad Parscale said in a statement.