In Don't think of an elephant, George Lakoff describes conservatives as guided by a "Strict Father" morality while liberals derive their values from a "Nurturant Parent" metaphor. Sorry, I think Lakoff is conceding to the right's frame as soon as he tries to describe US politics within family values metaphors.
Lakoff, drawing on "Focus on the Family" honcho James Dobson's child rearing prescriptions, notes that Strict Father types believe we are born bad and need to be kicked into line as children by a father (standing in for their God, I guess.) Once we've been so kicked, we'll know how to behave obediently and so will be rewarded with plenty and properly shun the undeserving whose unworthiness is demonstrated by their poverty and suffering. Meanwhile Nurturant Parent people think we are born good, that we respond well to empathy (and their God embodies infinite love), that parents teach responsibility to children by encouraging caring, freedom, fairness and open communication.
If I had to pick, I'd identify with the NPs. But actually, I don't play inside these family-centered bounds -- nor do I think US politics is actually stuck in them. The root political actor within the US system has historically been the free person/citizen, a category that has been extended through great struggle to include many previously excluded persons beginning with white males not owning property, then women and people of color -- and currently being stretched in the direction of gays and other gender deviants.
Looked at from the stance of the free political actor, the conservative paradigm looks like the abused child's worldview: perpetually powerless children try to either emulate or placate the worst playground bully on the lot. Alternatively, liberal political morality depends upon the mature adult who has learned to make personal moral choices while recognizing that no individual has all the answers. Within the understanding that the actor is the person, not the family, Lakoff's description of the liberal values of responsibility, empathy and protection reads mostly true.
Family values metaphors pick at and activate the scars individual and groups carry in a society that has historically consigned them to permanent childhood. That's okay with conservatives -- theirs is the morality of the Great White Father; they want to get and stay on top. This is powerful stuff: we are deeply conditioned to respond to childhood hurts (including new ones inflicted in adulthood.) Conservatives sell defensiveness, fear, and we've mostly had enough experience with pain and powerlessness so that fear sells.
Truthful frames for liberal values speak to the emerging, never fully actualized, adult within us. They evoke our aspirations, our hopes. Hope can dangerous; it often requires a leap of faith. Bold leaps are at the core of liberal values; courage is their essence from which empathy, generosity and responsibility flow.