President Simon Hughes has challenged Liberal Democrats to win half Wales' parliamentary seats within 20 years.
He set the target at the Welsh Lib Dem conference, where the party hopes it can increase its total of two of 40 Welsh MPs at the general election.
Mr Hughes called for a "crusade" to achieve a majority by the year 2022.
Meanwhile, leading Lib Dem Mike German urged caution on a Tory suggestion of an anti-Labour coalition in the Welsh assembly.
Mr Hughes, the MP for North Southwark and Bermondsey in London, told the conference in Cardiff that in 1922 the Liberals held a majority of Welsh seats, and he "demanded" that the Lib Dems repeat the feat 100 years on, "at the very latest".
Party leader Charles Kennedy had to pull out of the conference because of the protracted parliamentary debate over the terror laws, and he would have told supporters that there were "no no-go areas" for the Lib Dems.
Mr Hughes emphasised that message, telling party members: "For the first time in our lifetimes we are making equal progress in rural and urban Wales."
He said: "As Charles has said on many occasions, there must be no limit on our ambition.
"If we think we can only take a short step, we will only take a short step."
On the new terror law, Mr Hughes accused the UK Labour government of being more authoritarian than the Conservatives and pledged that his party would vote to repeal the act which was eventually passed on Friday after a marathon debate.
He compared the measures to Tony Blair's government. "The bill is incapable of being well reformed: it needs to be replaced."
Meanwhile, Mr German, who leads the six Lib Dem assembly members, warned against entering a coalition with the Conservatives and Plaid Cymru to keep Labour out of power in Cardiff Bay.
Charles Kennedy thinks his party can gain at least one Welsh seat
Nick Bourne, leader of the assembly Tories, suggested the idea last week. Labour has a bare majority of 30 AMs in the 60-member assembly.
But Mr German told the conference: "Whilst we would never rule anything in or out - it would be unwise to do so - I would urge caution. You know this all appears an unlikely alliance."
The Lib Dems were previously in coalition with Labour in the assembly. But Mr German told his conference on Saturday that Mr Bourne was "flying a kite," and Lib Dems "should not be deflected from our only aim - winning seats at the coming general election."
Mr German, who was First Minister Rhodri Morgan's deputy during the coalition period, accused him of "being in government, but not governing".
He claimed it was Labour at Westminster rather than in Wales giving the directions and claimed Labour MP s were so worried about losing seats that they wanted to "override democracy".
"Rhodri is so pleased to be driving the train, he's completely lost sight of where it is heading," said Mr German.
"He's not noticed that the Labour assembly government train has run out of steam and is about to go off the rails."