Mr Jim Mitchell's leadership challenge is about saving Fine Gael, according to party activists and supporters in his Dublin Central constituency.
"I don't think he's doing it for anything else. There's no ego in it," said Mr Derek Bunyan, who has worked with Mr Mitchell at elections.
"Jim is doing this because Fine Gael is up the creek at the moment. It's the right time for him," according to Mr John Kearney, a former city councillor who also worked on Mr Mitchell's election campaigns.
Mr Mitchell's work on the DIRT inquiry impressed Fine Gael activists in the constituency. "It has been said that the Public Accounts Committee really brought this thing forward. People were very impressed," Mr Bunyan said.
His organisational skills were the outstanding qualities he had over Mr Bruton, Mr Kearney added. "He runs a very professional organisation with clearly defined structures. He runs it like a business."
Fine Gael needed this quality, Mr Kearney added. "The organisation is in a mess . . . John Bruton, for all his qualities, is just not a great organiser."
Mr Tommy Morris, a former programme manager and special adviser to Mr Mitchell, said the former minister was committed to doing what was best for the party.
He said that, after announcing his retirement, Mr Mitchell stood at the last election to ensure the party would not lose its seat in Dublin Central, and he agreed to stand in the European elections at the behest of the party. "Jim Mitchell never, ever refused to do things for the party," he said.
The hundreds of cards and letters Mr Mitchell received when he returned home after his liver transplant were testimony to his popularity, he added. "We need to generate enthusiasm like there was in Garret FitzGerald's time," he said.
Colleagues of Mr Mitchell do not see his health problems as a hindrance. "He has had his problems but he's 53 and I'm 38 and I can't keep up with him. He's back in the gym and full of energy," Mr Bunyan said.
In a joint statement last night, Mr Mitchell and Mr Michael Noonan said that in the wider Fine Gael organisation "there has been an absolute ground swell of support for the motion" of no confidence in Mr Bruton.