A clear division has emerged between the Conservatives, on one side, and Labour and the Liberal Democrats over the role of the state in helping disadvantaged children.
David Willetts, the Tory shadow cabinet member with responsibility for the family, stood out from children's secretary Ed Balls and his Liberal Democrat shadow David Laws by stressing the limits of state involvement.
The three frontbenchers were speaking at a debate organised by Barnardo's seeking to push children's issues further up the electoral agenda.
Willetts, whose official role is shadow minister for universities and skills, said public spending had risen by 50% since Labour came to power but he warned it would be "hard to sustain the levels of spending" in the years to come.
"We are now operating in an environment of tough times. In every decision we make we'll have to try to protect the family," he said.
Asked about the care system, Willetts said he had met relatives of children who had not been allowed to care for the child, who had then been placed in care.
"We need to be more imaginative about the alternatives to care," he said.
And, on the question of children in poverty, Willetts said that if the problem could be solved by public expenditure alone, Labour would have eliminated it.
"The public spending solution doesn't get to the heart of the problem," he said. "That's why the voluntary sector and a more flexible approach are going to be essential to make progress."
Balls said Labour had cut the number of children in poverty by one million by investing in their support since 1997.
"The opposite of that is spending less and leaving people to their own devices.
Don't ghettoise the welfare state," he told Willetts.
He also emphasised the importance of early intervention to support troubled families - but he criticised the Tories for not promising to protect budgets.
Laws described improving the life chances of disadvantaged children as the biggest domestic challenge facing the new government - but he warned that the Conservatives' taxation priorities of cutting inheritance tax and giving tax breaks to married couples "would only widen inequalities".
On the issue of state intervention in family life, he said his experience as a constituency MP had taught him that councils were "maybe being too patient with parents who often acted in a neglectful way".