"Uncle Sam," "founding fathers," "sending sons into war": all of these phrases speak to a universal metaphor in political life, one which equates the nation with the family. That sounds warm and cozy until you hear a Berkeley linguist ask what kind of a family this is.

In fact, there are two broad kinds of idealized families and they are at odds with each other, according to George Lakoff, professor of linguistics.

Lakoff is the author of a new book, "Moral Politics: What Conservatives Know That Liberals Don't," published by the University of Chicago Press. In the book, Lakoff proposes that conservatives and liberals split the political world into opposing camps, based on different ideals of family life­specifically the "strict father" model for conservatives and the "nurturant parent" model for liberals.

These ideals are so powerful in the lives of American citizens that they shape most, if not all, liberal and conservative views on political issues, he says. He adds that the family metaphors are inclusive enough to accommodate complex variations in liberal and conservative philosophies.

Lakoff supports this theory by demonstrating how the two versions of parental morality track onto national politics in a multitude of contemporary issues, including abortion, multiculturalism, social programs, crime and environmental regulation.

"Politics is not about neutral rational discussion of issues...(but) what version of family-based morality we are going to have," said Lakoff.

"Conservatives know this, but liberals have been slow to understand that they also have a family-based morality stemming from notions of how to raise children," he said.

Conservatives' Moral Strength

The "good" father seeks to develop self-discipline in his children by using rewards and punishments. Punishment is seen as nurturing in that it teaches discipline, self-reliance and respect for authority.

"To be morally strong, you must be self-disciplined and self-denying. Otherwise, you are self-indulgent and such moral flabbiness ultimately helps the forces of evil," said the linguist.

Carried into the political realm, this moral system­with strength at the top of the list of values­leads to the belief that "your poverty or your drug habit or your illegitimate children can be explained only as moral weakness and any discussion of social causes cannot be relevant," Lakoff explained.

Liberals' Nurturance

The "good" parent, therefore, develops the child's capacity to achieve happiness by being empathetic and teaching responsibility. This was originally a mother's model, said Lakoff, but is now widely expressed by both sexes.

In this moral system, obedience comes out of love and respect for the parent, not out of fear, and strength is in the service of nurturance.

Carried into the political realm, morality as nurturance means that citizens are able to empathize with people who have different values and backgrounds, he said.