Liberal Democrat leadership hopeful Chris Huhne has said that rather than being a "bridge to the future" he could deliver results for the party now.
Mr Huhne defended his decision to travel by plane
The former MEP, who only entered parliament last year, insisted he had the ideas to "set the pace".
Launching his manifesto, Mr Huhne said he would fight for civil liberties and attack Labour's "surveillance state".
Earlier, rival Simon Hughes urged Lib Dems not to play safe, seen as a dig at third candidate Sir Menzies Campbell.
Mr Huhne, a former journalist and the party's economics spokesman, launched his leadership manifesto at Green Works, a London workshop where unemployed and disabled people refurbish unwanted office furniture for community groups.
The launch was put back two-and-a-half hours due to foggy flying conditions, which delayed Mr Huhne's arrival in London.
Explaining why he had flown rather than travelled by more environmentally-friendly train, he said would be making sure his campaign was carbon neutral.
Explaining the ideas in his manifesto, he said: "I have the ideas to set the pace.
"Liberalism is the last of the great systems of values and ideas, as relevant today as ever because it puts the individual at the heart of politics. It is politics where people matter."
He added: "I will not be a bridge to the future, because I am ambitious for our party now."
Mr Huhne's manifesto, which is available online, stresses traditional Lib Dem concerns such as civil liberties, the nuclear deterrent and the environment.
It also emphasises the importance of decentralisation of the British state, which Mr Huhne dubbed "the most centralised and monstrous bureaucracy in Europe".
His manifesto also pledges to roll back the "security-obsessed surveillance state" and calls for a "more flexible and small-scale deterrent" to replace Trident.
Mr Huhne also restates that the rich should pay more tax and says that British troops should pull out of Iraq by the end of 2006, saying they were "part of the problem not part of the solution".
"If you don't have a firm deadline things slip," he told reporters.
He stressed the importance of internationalism, saying he backed the "rule of law not the rule of war".
Lib Dem MP Susan Kramer, one of Mr Huhne's chief backers, said he had started as an outsider but was rapidly gaining momentum and had picked up the support of a further three MPs in the past week.
Mr Huhne said he had 22 backers across both Houses of Parliament.