OUR NOTIONS OF EQUALITY HAVE BEEN SHAKEN this week by two wildly different stories in the news. One involves the death penalty, the other a "weight" penalty.

The United States Supreme Court on Thursday ruled 6-3 that "mentally retarded offenders" (usually defined as having an I.Q. of 70 or below) have less "relative culpability" in capital crimes than the unretarded.

Executing the mentally retarded is unconstitutional, ruled Justices Sandra Day O’Connor, Anthony Kennedy, David Souter, Ruth Bader Ginsburg, Stephen Breyer and John Paul Stevens, because "The practice…has become unusual, and it is fair to say that a national consensus has developed against it." They held that it therefore violated 8th Amendment prohibitions against "cruel and unusual punishments."

"Counting the 12 states that do not allow capital punishment at all," wrote Associated Press reporter Anne Gearan, "30 states prohibit execution of retarded people. The number of states that banned the practice increased ninefold between the court’s last ruling on the issue [1989] and the time it heard arguments in [this] case [Atkins v. Virginia, 01-8452]."

In the 20 states that have permitted execution of the retarded, writes Gearan, "Dozens or perhaps hundreds of inmates…will likely now argue that they are retarded, and that their sentences should be converted to life in prison." That’s what intelligent people would do.

What this ruling means, of course, is that some Americans are now immune from the death penalty. If your I.Q. is 71 and you commit murder, you go to the gas chamber or electric chair. If your I.Q. is 69, then like James Bond you have a "license to kill" and are immune from execution.

Leftist opponents of the death penalty have long argued that the executioner’s axe falls mostly on the poor and the black because rich whites can afford top-notch lawyers and because racial minorities are purportedly more likely to get arrested and convicted. Rich whites were thus said to be immune from the death penalty. Such claims are, to say the least, disputed. Use of the Federal death penalty, as Attorney General John Ashcroft argued, has been biased against whites.

A recent tactic used by death penalty opponents, as this column analyzed, has been to seek clinic evidence of brain "abnormalities" or "defects" in those on death row, and to invoke these in "twinkie defense" claims that the killer was not responsible for his actions. This variation of the "insanity defense" implicitly makes the ugly assumption that those who murder (or commit other heinous capital crimes) can be mentally healthy. And it begs the logical question: if a brain defect inclines someone to kill, isn’t this an even bigger reason to remove him permanently from the gene pool and society forever by executing him?

Now these same Leftists want to invoke low I.Q. as tantamount to insanity, and to make the stupid among us a privileged class immune from execution.

But are not these the same Leftists who dismissed claims that blacks as a group score lower than whites, and whites as a group score lower than Asian-Americans and Jews, on I.Q. tests because the tests are defective or culturally biased? (And would not using such defective, biased tests therefore unfairly be more likely to lead to the execution of Asian-Americans and Jews than of blacks or whites? Hey, isn’t this how the ACLU reasons?)

I.Q. test scores also vary significantly because of the amount of sleep the night before, what the test-taker had eaten, whether the person had a brain-stimulating cup of coffee before being tested, the color of the room in which the test was taken, and many other confounding factors. If we add to these the incentive of an inmate to save his life by scoring lower than 71 on such a controversial test, would you want to stake a person’s life or death – or society’s justice and safety – on whether a test "measured" his I.Q. as 69 or 72?

Southwest Airlines found itself at the center of controversy this week. It reportedly announced that, starting June 26, passengers its agents subjectively regard as too big or fat to fit "comfortably" in one seat will be required to pay for two seats. Southwest now says that it has had this seldom-enforced policy since 1980, and that American, Continental, Northwest, US Airways, and several other airlines have similar policies. (Delta and United Airlines reportedly do not.)

"If people are taking up two seats, they ought to pay for two seats," says David Stempler, president of the Air Travelers Association. "They are really impinging on the sense of fairness."

Among the many questions set swirling around this unequal treatment of passengers are these: is being obese a person’s fault for overeating – or are such people victims of a health problem or of their inherited genes, the DNA blueprint with which they were born?

Is clinical obesity for some people an "immutable trait," like skin color, as defined by Title VII of the Civil Rights Act? If so, then to charge a higher airfare to such obese people could constitute "invidious discrimination." It might also violate the Americans with Disabilities Act.

Many are fat from overeating and a sedentary lifestyle, of course, but is Southwest Airlines qualified to charge these people for two seats while not doing so and making the legally-required "accommodation" for those who are obese for medical or genetic reasons? And if obesity is more common in some racial groups than others, does charging the obese passengers more constitute, by "disparate impact," de facto racial or other discrimination?

If the issue for Southwest is that some people require more than one seat, is it prepared to require that two seats be purchased by pregnant women, those in wheelchairs who require more than one share of space and flight attendant time and effort, tall people who take up more than one share of leg room, those who subjectively smell "bad" and hence take up more than their share of airspace in the airliner, and so forth?

Those required to purchase two tickets, we must presume, are entitled to two meals, two times the number of "frequent flier" miles, twice the attention of flight attendants, and double the luggage weight allowance and any other benefits an airline accords to passengers. To provide anything less would itself be discriminatory, no?

President Bush on Thursday launched a "Healthier US" initiative to improve the fitness of Americans. Whether this will later dovetail with the growing drumbeat to tax fattening foods remains to be seen. As reported in the April 9, 2001, Washington Post, Bush friend and prospective Surgeon General Dr. Kenneth Cooper has proposed giving up to $1,000 in tax deductions for those who meet government standards for body mass (thinness), healthy blood pressure, healthy cholesterol levels, and not smoking. The implicit flip side of this, of course, would be a Darwin burden of higher taxes on those already facing heavier health burdens.

One out of four Americans are "obese," 20 percent or more above healthy body weight. Sixty-one percent of Americans are overweight. This, say some, increases our nation’s healthcare costs by $117 billion each year. Others say that much "junk science" surrounds the obesity issue.

But this much seems clear. If one in four of us is obese, and if Americans are getting fatter all the time, then this cannot be called an "unusual" condition.

Southwest Airlines in a free enterprise society should have every right to make its passenger seats as large or small as it wishes – and to ask those unable to fit into one seat pay for two. Airlines typically have little metal cages into which passengers can test their carry-on bags to see if they meet size requirements for fitting beneath seats or in overhead compartments. Will Southwest soon have a test seat in its ticketing area into which would-be passengers must "comfortably fit" their backsides or be required to buy two tickets? (At least this would provide an "objective" measure, in contrast with the proposed subjective whim of the ticket-seller about whether a customer is "too fat.")

Today’s Southwest Airlines seat is 18-3/4 inches wide, just over what in biblical measure was called a "cubit," the typical distance from elbow to longest fingertip. Using this subjective measure, Noah built his Ark. The Bible does not indicate whether he charged elephants twice as much as gazelles to board the Ark, which was not legally defined as a public accommodation. The Ark was open, we are told, only to those not condemned as sinful. Sheep were divided from goats, but not fat from thin, on this craft.

(I remember once flying from New York to Brussels via now-defunct Capitol Airlines. It was cheap, but passengers were literally crammed together like cattle in a railroad boxcar, with your face forced into the hair of the passenger sitting in front of you. Lots of people flew Capitol once, but apparently few flew it twice.)

The market test Southwest may have to make is whether today the statistically average, or mean, seated American backside measures more or less than 18-3/4 inches wide.

In free enterprise, the customer in the end is always right…and the customer’s end will be the deciding factor. By charging the overweight less than the cost of two tickets, a new Big Backsides Airlines could make a killing, as soon as airport slot space that had been monopolized by soon-to-be-defunct Southwest Airlines becomes available.