Nick Clegg will plead with Liberal Democrats to hold their nerve and accept "vitriol and abuse" as the price of proving to voters they have now become a serious party of government.
The Deputy Prime Minister will warn against a return to the comfort zone of being a party of opposition and set out his vision of the party's future beyond the 2015 general election.
His keynote conference address to activists in Brighton comes after a stormy week in which the party has suffered a backlash over plans to squeeze the rich and strip wealthy pensioners of state handouts.
Amid dire opinion poll ratings and rumblings about his leadership, Mr Clegg has attempted to play up his determination the well-off will bear the brunt of another round of spending cuts as the coalition struggles to balance the books.
His position was given a much-needed boost earlier in the week when the conference resoundingly rejected a call to tear up the Government's deficit reduction strategy.
And Mr Clegg will insist that the difficulties facing the party "will be worth it" if the economy begins to improve as it will propel the Liberal Democrats from being the UK's third party to "one of three parties of government".
"Be in no doubt. If we secure our country's future, we will secure our own," he will say - explicitly linking his party's future with the success of the power-sharing administration's efforts to turn around the economy.
Mr Clegg, who came into the conference on the back of making a public apology for an election pledge to oppose any rise in tuition fees which the party abandoned after taking power, will concede presiding over "some real disappointments".
But he will warn against the "alluring prospect" of swapping coalition Government for a return to the years of engaging in the politics of protest and opposition. "I know that there are some in the party - some in this hall even - who, faced with several more years of spending restraint, would rather turn back than press on. Break our deal with the Conservatives, give up on the coalition, and present ourselves to the electorate in 2015 as a party unchanged. It's an alluring prospect in some ways.
"Gone would be the difficult choices, the hard decisions, the necessary compromises. And gone too would be the vitriol and abuse, from right and left, as we work every day to keep this Government anchored in the centre ground. But conference, I tell you this. The choice between the party we were, and the party we are becoming, is a false one. The past is gone and it isn't coming back. There's a better, more meaningful future waiting for us. Not as the third party, but as one of three parties of government."