There is a thin line between healthy challenge and insanity.

HEBER SPRINGS, Ark. – We have pulled our speed boat into a cove here at Greers Ferry Lake and cut the engine.

The shoreline is not quite a shore at all. It’s a steep stone cliff. My wife, our friends and I guess it to be at least 30 feet tall. As we make our estimates, we notice a boy just over halfway up the rock face.

My nerves tighten as I imagine him unable to go higher but afraid to leap out and fall back in the water below. But he finally finds a foothold and pulls himself to the top. At which point another boy begins to work his way up the cliff.

“That’s how we lose people,” says my friend, who lives at this lake for part of the year. “At least one person a year dies doing stuff like that.”

The second boy, now two-thirds of the way up, hesitates, looking for an angle, an anchor, something. His friend above tries to guide him. It works, and soon both lads are standing on an outcropped boulder at the top of the cliff, looking down to where friends or family in a boat await them.

One by one, they edge out to the end of that rock and, suddenly, hurl themselves feet-first into the lake. Our hearts stop until each surfaces safely.

There is, I have concluded, a thin divide between healthy challenge and insanity. Those boys imagined that the cliff was the former. For me, several decades older, climbing it would have been the latter. The question is how we gather enough discernment and maturity to tell the difference.

This question is not one simply for people taking a weekend off at the lake. Rather, it insinuates itself aggressively into all parts of life. It even insists that the people who set and execute national public policy wrestle with it.

For instance, is it an unavoidable challenge to go to war or is it simply testosterone run amok? When the United States and the Soviet Union went eyeball-to-eyeball 40-plus years ago in Cuba, was it because Nikita Khrushchev lacked the ability to make a reasoned decision and chose, in effect, to scratch his way up and jump off a 30-foot cliff? Is that also why Saddam Hussein barged into Kuwait in 1990 and President Bush ordered the invasion of Iraq this year? Or was something else at play?

Maybe we all could learn from Niccolo Machiavelli, who wrote this in “The Prince”: “A man’s wisdom is most conspicuous where he is able to distinguish among dangers and make choice of the least.”

Our models run to extremes. We can be Hamlet, who struggled to decide even whether to be or not to be. In the same cautious camp is J. Alfred Prufrock, T.S. Eliot’s poetic character who muses about whether he dares even to eat a peach. Or we can be Evel Knievels or extreme sports stars who seem to abandon any sense of caution to risk death.

It’s important, as I say, not only for each of us to figure out a balance between fear and recklessness, but also for us to be able to discern where on the continuum the leaders we elect fall. Do we want people whose first instinct is to fight, to accuse, to spend money on guns over butter? By contrast, what kind of threats will overtake us if we elect leaders who are so fearful of confrontation that they appease evil?

And the risks are not all military, not all about physical violence. Some people lack good judgment when it comes to financial matters, too, preferring to risk everything on the throw of the dice rather than making safer investments that may not get the heart racing. And our divorce courts are testimony, in part, to a widespread failure to analyze risk and reward in relationships.

In our culture, danger lurks everywhere. Just crossing streets is risky. It’s hazardous to get in our car and drive to work. And since the Sept. 11, 2001, terrorist attacks, many of us feel more vulnerable to risks over which we seem to have almost no control.

But we cannot let danger paralyze us. If we dread life, we won’t understand that each day is a delicious gift of common grace to be inhaled.

As we start the engine and leave the cove, I marinate in the wind – and silently hope our driver doesn’t recklessly kill us.

Bill Tammeus is an editorial page columnist for The Kansas City Star.