Roughly one in five Americans define themselves as "liberals" with about one in twenty claiming to be "very liberal." Most, if not all of us, define ourselves in that way because of what we believe (or say we believe) about what's right and what's wrong politically.

Jonathan Haidt, a brilliant social scientist at the University of Virginia contends that we actually make those decisions about what's right and wrong well before we actually begin to justify those decisions, either to ourselves or to others . . . and that there are distinct and measurable differences between how Republicans and Democrats, conservative and liberals, make those decisions.

Haidt's studies clearly imply that we're hard wired to "lean" heavily in one direction or another when we make political decisions.

After we jump to a more or less hard-wired decision, Haidt observes, we then do our best to justify our leanings, both to ourselves and to others.

It's as if we all have a little lawyer or PR agent in our head, to make up a plausible story to justify what we've already, instinctively, decided to do.

Six of those moral instincts them have been well identified, and many of the ways they move us have been experimentally tested and confirmed. They are:

1. Justice. Most, if not all of us, conservative, liberal, and otherwise, react instinctively to any hint of injustice or unfairness. We don't like cheaters. We also tend to be naturally fond of avengers.

2. Harm. We all respond similarly to any hint of physical danger, to ourselves, to our family or to our "team" or to others. Most of us, conservative and liberal, hate seeing people hurt.

3. Liberty. Most of us instinctively love freedom and react viscerally to any hint, in word or deed, of oppression. We really don't like bullies.

4. Loyalty. Most of us despise betrayal of devotion. We're family people who don't take kindly to folks we think are "outsiders." We love the country. We love the Corps. We don't think about it. It's just so.

5. Respect. We also react viscerally to those who show a lack of respect for authority, whether it be the head of the family, a professor, a boss or the chain of command.

6. Reverence/Disgust. Finally, we react viscerally, Haidt has shown experimentally, to things that we find disgusting, as well as to things, attitudes, or ideas often defined in terms of religion or our personal transcendent sense of awe.

All of us, conservative and liberal, Haidt finds, respond viscerally to stimuli in all six areas. Reaction neurons fire, demonstrably and predictably, well before neurons associated with rational thought light up in all six areas.

Self-identified Liberals differ demonstrably from self-identified conservatives, however, in how they handle conflicting stimuli.

Statistically, liberals are more likely than conservatives to allow gut reactions about Justice and Harm to override their gut reactions about Loyalty, Respect, and Reverence.

It's not that we don't have the same gut reactions in those areas as our conservative friends, it's just that, statistically, we tend to give them less weight when we make ethical decisions.

The ideal ethical decision for a conservative or liberal is thus fair, helpful, freely arrived at, loyal, respectful and reverent. If pushed, however, liberals will tend to allow considerations of justice and harm to override all other considerations.

Over time, that means we liberals tend to be statistically more fair than respectful; more protective of the weak than loyal to authority.

That can be really annoying at times, especially to those in power.

A liberal at his best, in the words of JFK, will be " . . . someone who looks ahead and not behind, someone who welcomes new ideas without rigid reactions, someone who cares about the welfare of the people — their health, their housing, their schools, their jobs, their civil rights, and their civil liberties [and] someone who believes we can break through the stalemate and suspicions that grip us in our policies abroad . . . "

Sometimes we succeed. Sometimes we fail.

The best of us recognize our limitations, but never stop trying to live up to a noble ideal.