Barack Obama, the former US president, has announced he is endorsing 81 Democratic candidates for the November mid-term elections after months of speculation about his involvement in the party’s campaign. 

Mr Obama posted a list of the names on Twitter in what was described as a “first wave” of endorsements, with a second list expected to come before voting.  

Former staffers such as Buffy Wicks in California and Andy Kim in New Jersey were on the list, but the left-wing firebrand Alexandria Ocasio-Cortez was not. 

The former US president is expected to appear on stage with some of the candidate as the Democrats attempted to win back the House of Representatives and, more optimistically, the Senate in November. 

Mr Obama wrote on Twitter: “Today I’m proud to endorse such a wide and impressive array of Democratic candidates – leaders as diverse, patriotic, and big-hearted as the America they’re running to represent.”

Mr Obama has largely avoided intervening in US politics since leaving office in January 2017, save for the occasional endorsement of a Democrat in a special election or coded criticism of his predecessor – who he rarely calls out by name. 

His endorsements come with the Democratic Party locked in an internal debate about how best to respond to its thumping defeat in the 2016 elections. 

That year Donald Trump unexpectedly won the presidency and the Republicans took control of the both the House and the Senate – a rare feat for a political party. 

The unexpected success of Bernie Sanders, the left-wing senator who pushed Hillary Clinton hard for the 2016 Democratic presidential nomination before falling short, has fuelled those demanding the party tack to the Left. 

The victory of Ms Ocasio-Cortez, the 28-year-old socialist who ousted a 10-term Democratic congressmen in a New York primary earlier this year, provided a vivid example of the split. 

Figures on that wing of the party are calling for the universal health insurance, the abolition of US Immigration and Customs Enforcement, known as Ice, and a more aggressive stance on corporate greed. 

The candidates Mr Obama has endorsed are running for a variety of federal, state and more local races across America. 

The Daily Telegraph talked to a number of the candidates on the list who used to work for Mr Obama earlier in the year about why they decided to take to front-line politics. 

Ms Wicks, one of the first people Mr Obama hired for his 2008 presidential campaign, explained that she wanted to fight the Trump agenda. She is running for the California State Assembly. 

Ms Wick, 40, said: “I learned so much from President Obama; his style of governing and who you are as a person.  

“Donald Trump is horrifying, I don’t even know how to put it into words. He is trying to undermine the Obama legacy at every turn.

“He is trying to roll back strong progressive politics. I want to do what I can to protect and build on what we achieved.”