News that the Southeast Asian earthquake and tsunami have killed 140,000 people stirs the compassion in us, but estimates that the war our nation started in Iraq might have caused an equal number of casualties inspires little more than a shrug of self-righteousness from many of us.

The tens of thousands of deaths we couldn’t prevent sadden us, but the tens of thousands we needlessly caused don’t? Is death more tragic when God or nature brings it about, but less so when we do it ourselves?

I’ve long been intrigued by the seemingly limitless human capacity for inconsistency. The deaths of 3,000 people, mostly Americans, at the hands of terrorists in 2001 dramatically altered the course of human events, but the deaths of 3,000 Haitians from last summer’s killer hurricanes hardly registered in the public’s consciousness.

We regard the 9/11 attacks as one of history’s greatest crimes yet the millions who have died in Sudan, Rwanda, The Ivory Coast and elsewhere in equally willful attacks merit, for many of us, little more than a sigh.

There are countless examples of our inconsistent regard of large-scale death. The number of victims most often associated with World War II is 6 million - the number of Jews massacred. Yet we often overlook the 16 million civilians in the Soviet Union alone who perished in the war.

The British medical journal Lancet in October published a study placing the number of Iraqi deaths since the American invasion at between 8,000 and 194,000 - with the most likely number statistically being the midpoint, 98,000. Yet I’ve heard many Americans dismiss Iraqi civilian casualties as a mere byproduct of war.

It seems that we’re more concerned about mad cow disease, which has killed about 140 people worldwide, than AIDS, which has killed more than 25 million.

I sometimes wonder if the human brain is wired to absorb the enormity of death on a mass scale. No other animal can even contemplate life at that level, and even for our species, the large-scale preservation of life has only been a topic of general discussion for maybe a couple of hundred years.

We are the only species capable of genocide, and the only one capable of mercy but we’ve had far more experience with the former than the latter.

Our inability to rationally process mass death makes us resort to arbitrary standards of analysis _ a death close to us is more important than 10 far away. A death we cause is more easily pardoned than one other people cause. Death by natural disaster is more regrettable than death by war.

The only thread connecting Iraq and Southeast Asia is the scale of human misery. In each case, the brain struggles to grasp the enormity of events yet in one case, it shrinks behind rationalizations, in the other case, it grieves in genuine empathy.

Scale also confounds us in terms of dollars we’re the only species on Earth to cope with budgets. Millions, billions, trillions what do they mean?

First, President Bush pledged a paltry $15 million in aid to the tsunami relief effort - about what we spend every three hours in Iraq. Then he upped the promise to $35 million - less than the $40 million in private donations pledged to finance his inauguration festivities later this month. Then he pledged $350 million, one-tenth of what was spent helping Florida recover from four summer hurricanes.

Even this seems threadbare compared to the need. Bush unwittingly acknowledged this himself, encouraging Americans to make private donations to the relief effort and drafting two former presidents to spearhead the effort.

By doing this, Bush effectively classified foreign disaster response as a matter of voluntary largess -like the funding of his inauguration rather than the moral duty of a wealthy and righteous society. Which American would have objected had Bush said, "We’re going to do whatever it takes, whatever it costs, to help those poor souls?”

Shame on us if we would begrudge a few billion to help deliver tents, clean water and tetanus shots to keep desperate Asians alive especially those of us who haven’t cared about the hundreds of billions we’ve spent in the process of killing tens of thousands of Iraqis.

But such are the cruelties of scale. Numbers numb us, allowing simple human compassion to get lost amid other priorities and rationalizations. Perhaps in a few hundred more years, when disaster strikes, the instinctive human reaction will be, ”How can we help?” not, ”How much will it cost?” or “Why should we care?”

Robert Steinback is a columnist for The Miami Herald. Readers may write to him at: One Herald Plaza, Miami, Fla. 33132, or via e-mail at rsteinback@herald.com.