Protection for the NHS and schools budgets should be kept in place after the general election, Nick Clegg has insisted.
The Deputy Prime Minister said retaining the ring-fencing as fresh cuts were made to public spending would be an expression of Liberal Democrat values.
The call came after Mr Clegg successfully saw off a challenge to the coalition's deficit reduction strategy at the party's conference in Glasgow.
The Lib Dem leader urged activists to "come together" after a motion endorsing the strategy was passed, arguing that they had to take ownership of the austerity measures. The party would suffer at the polls if it was seen to be merely a "passive recipient" of tough Tory fiscal discipline.
Mr Clegg said he had fought after the last election for schools budgets to be given the same protection as the health service.
"We have done that between 2010 and 2015," he said. "My personal view, and we will have to discuss it, but my personal view is we should do that again for 2015 to 2020. And make sure that one of the bedrocks of our approach, our Liberal Democrat approach, is that as we continue to make savings, as we clear the decks up to 2018, we do not make savings in the schools budget and the NHS budget - which I do not think is consistent with our views."
Polls have suggested that Lib Dem activists would prefer to be in coalition with Labour, but Mr Clegg warned that any deal would not be easy. He said he had heard members saying it would be "nicer to be in a coalition with this party".
But he told them: "Don't go into coalition if you want to have a nice time. It's not a walk in the park, it is hard work, battling out these compromises. It's a constant, daily - not trial, but you need to really dig deep every day to make sure that we don't allow our values to be compromised, that we do stand up for ourselves.
"I personally think, I really feel this very strongly, that will be the case whoever you are in coalition with. Being a smaller party in any coalition government is a great privilege, of course, but it means whoever you are in coalition with you need to make sure your voice is heard."
He indicated that his speech on Wednesday would involve setting out how he made choices about which battles to fight, "where you dig a trench, what you call a red line".