Liberal Democrat leadership candidate Chris Huhne has called on the party to fight the government's "serious slide towards authoritarianism".
He said in a speech to the Demos think tank that Lib Dems should not just focus on "bread and butter" issues, but defend civil liberties.
Mr Huhne, a party Treasury spokesman, criticised Labour's anti-terror measures and plans for ID cards.
Sir Menzies Campbell and Simon Hughes are the other contenders to be leader.
'Cumulative effect'
In his speech, Mr Huhne said government measures such as the Racial and Religious Hatred Bill, Identity Cards Bill and the Terrorism Bill were "illiberal".
This had had a "cumulative effect", which it should be the Lib Dems' "priority" to overcome.
Mr Huhne said: "Labour still believes that the man in Whitehall knows best. We Liberal Democrats do not.
"We believe that real liberty means power cut into pieces. That is the key reason why we favour decentralisation and the devolution of power to local communities."
One of the "crucial divisions of opinion in Britain in the future will be between the party of civil liberties and the party of authoritarianism," he added.
Labour was peddling a "fantasy" of a "risk-free world" could be created by legislation.
Mr Huhne said: "It is worth remembering, however, that all of us are minorities at one time or another."
He added: "We all of us need the protection which rule of law gives us."
Liberal Democrat members are currently deciding whether to elect Mr Huhne, foreign affairs spokesman Sir Menzies or party president Simon Hughes as leader.
The result is expected on 2 March.
^ Back to top | BBC Sport Home | BBC Homepage | Contact us | Help | ©