Voting started today in the race between Sir Ed and Layla Moran, who was elected to Parliament in 2017.
In an interview with the Evening Standard, Sir Ed said his party was facing the greatest challenge he could remember, but outlined his determination to make the Lib Dems a political force again.
He said: “There is a danger that we mustn’t be, or become, a party for the middle-class graduates.
“Psychologically we’ve been doing particularly well in graduates. Whether that’s our message on Brexit, on climate change, I don’t know.”
But he said there was “no quick fix” or group of people they could go after to solve the party’s problems.
A report co-authored by Tim Bale, politics professor at Queen Mary University of London, said the Lib Dems have a new core vote comprised of university graduates. It suggested that the Lib Dems have a new heartland, a “yellow halo” of electoral strength in London and the South-East.
But Sir Ed said the party could win seats across the United Kingdom.
He added: “You bet I want to be in power. I’m not going to sit here and tell you we’re going to win a majority next election.
“But we can be a party of influence, a party of power, working with other progressives. Once we’re in a position of strength — let’s see what happens.”
He said Labour leader Sir Keir Starmer was not as “toxic as Corbyn” and hinted that he was open to working with him. “Maybe Keir Starmer will be thinking, well I’m not going to win by myself, and be looking for parties that have got common ideas…”
After an election campaign centred on stopping Brexit, described afterwards by the party as a “car crash”, the Lib Dems ended up with 11 MPs in December, one fewer than in 2017. They also lost all the MPs who defected from other parties who had helped swell their numbers to 21 pre-election.
Sir Ed, who served as energy secretary in the Conservative-Lib Dem coalition, has put care at the heart of his pitch and has opened up about his personal experiences of looking after family members.
The father-of-two described caring for his disabled son John, 12, who has an undiagnosed neurological condition and cannot walk or talk.
Most mornings the MP for Kingston and Surbiton gets John ready for the day, adding: “I go in and say hello to him and just have a cuddle and I chat to him.
“And then we get him up and start massaging him. He can’t get out of bed himself, he can’t go to the toilet himself, dress himself. That’s the level of disability.
“My dad died when I was four and then my mum became terminally ill when I was 12. I nursed her with my brother until she died when I was 15.
“As a young carer and a young person that’s quite challenging period in your life, it has a real impact on you.”
Sir Ed was then looked after by his grandparents and also cared for his grandmother when she grew frail.
He added: “Caring for my mum, caring for my grandparents, my son, has taught me what so many people in our country go through.
“I want the Liberal Democrats to be the voice of carers and I feel I can bring something to that discussion, something to that representation of carers.”
It is the second time he has run for leader after he and Ms Swinson went head-to-head last year when Sir Vince Cable stood down. The new leader is due to be announced on August 27.