Liberal Democrat UK leader Charles Kennedy has vowed to campaign on "principles and values" at the upcoming general election.
Mr Kennedy hit out at negative campaigning
Addressing his party's Scottish conference in Perth, Mr Kennedy condemned negative campaigning.
He also attacked "authoritarian" Labour and stressed the achievements of the Lib Dems in influencing Scottish Executive policies.
But some members said the party is too comfortable with coalition politics.
On the government, the MP for Ross, Skye and Inverness West, said: "We've seen it over trial by jury, we're seeing it now over house arrests, we're seeing it equally over identity cards - whenever they are presented with a genuinely difficult problem - it is so revealing about Labour in power at Westminster, their instinctive reaction is an authoritarian reaction."
Mr Kennedy also raised concern over the international situation in Iraq and called for the government to "publish and be damned" the legal advice for going to war and called for a "timetable for phased withdrawal".
He claimed that nationally, politics was now genuinely a three party system, and that in Scotland the LibDems were responsible for key executive policies.
Mr Kennedy told delegates: "Free personal care for the elderly - delivered, abolition of tuition fees - delivered, no top up fees - delivered, free off peak local bus travel for pensioners - delivered, cutting primary class sizes - delivered.
"Don't let the Labour party go out at this election and somehow claim all the credit for these initiatives.
"The difference between what Labour has done in London and what the executive has achieved here in Scotland is in large measure down to the presence of the Liberal Democrats.
"We are the added value in the politics of this country."
He credited Scottish party leader Jim Wallace and Lib Dem Transport Minister Nicol Stephen for the abolition of the Skye Bridge tolls.
And he pledged a tax rise for top earners of more than £100,000 a year, from 40p to 50p, to pay for better pensions, child care and scrapping the council tax.
Scottish leader Jim Wallace (left) will give his address on Saturday
Mr Kennedy went on to herald what he believes will be the most exciting general election for a generation, insisting "I can't wait".
The leader received a standing ovation for a speech that signals an effective start to Lib Dem campaigning.
Before the conference, a Liberal Democrat MSP expressed concern about his party's coalition with Labour in the Scottish Executive.
Donald Gorrie has said that they are too comfortable in Labour's shadow.
But Scottish leader Jim Wallace said he was confident his party was maintaining its identity in voters' eyes.
Mr Gorrie, a Central Scotland MSP, said he was speaking for many party members over concerns about the Lib Dem profile within the coalition government.
His comments echo a leaked party document in saying too many good Lib Dem ideas have been allowed to be presented as Labour initiatives.
Mr Gorrie argues that not only should the party be cleverer about managing its image but it should be more prepared to "rock the boat" over executive policy.
And he said that the party might be well advised to rule out a third partnership deal after the next Holyrood elections.