Former cabinet minister Sir Ed Davey has ruled out running for the Liberal Democrat leadership, appearing to leave the way clear for Sir Vince Cable to take the job.
The former energy secretary said it was a "difficult" decision not to stand but was based on the desire to spend more time with his young family.
The Kingston and Surbiton MP's decision not to run comes after other potential contenders Jo Swinson and Norman Lamb ruled out standing.
Former business secretary Sir Vince is the only declared candidate to replace Tim Farron, who announced he would quit because he had been unable to reconcile his Christian faith with the demands of leading a "progressive, liberal" party.
Writing on the Liberal Democrat Voice website, Sir Ed said his decision came after a camping trip with wife Emily and children John and Ellie.
"I've come back to Westminster more determined than ever to campaign hard for the party Emily and I both love, but not to campaign to lead the party at this moment," he said.
Setting out the personal reasons behind his decision, the Lib Dem home affairs spokesman said: "Our joy this weekend was seeing our two children play together.
"And when you understand that John (aged nine) is severely disabled, you will appreciate that seeing our three-year-old daughter make him laugh is quite special.
"And if it helps explain my decision not to run just a little more, please remember that my father died when I was four and my mother when I was 15.
"Being there for my children over the next few crucial years and to see those special moments is my personal priority.
"So my decision not to stand now to be leader of our party is a difficult one, but it is rooted in my family: the need to be there for my young children and not continually away from home; the need to protect my family from the inevitable intrusion on our lives; and the need to protect myself from pressures that would otherwise compromise my job as a father while they are still so young.
"And this was a difficult decision, because I want to play a big part in rebuilding our party, and taking it into power, at all levels of government.
"If I'd run, my message would have been simple: we need to be the party of reform, challenging the status quo.
"Saying the uncomfortable things. Recognising how broken our politics is."
He said the LIb Dems had to be "super ambitious", drawing inspiration from Emmanuel Macron's success in France.