ATVs like the one Diezel De Rupp was on can go as fast as 65 mph, weigh 500 pounds or more, and are notoriously unstable, but regulations are just a step above those for bicycles, even for kids. Most states set no minimum age for being a passenger or for driving ATVs on private land. While some states prohibit very young kids from operating ATVs on public land, it's generally OK if someone older with a driver's license provides "supervision." Utah is the only Western state with an absolute minimum age -- 8 years old -- for driving four-wheel ATVs on public lands. "They don't like any laws against their great machines," says Rabe.

The industry's ATV Safety Institute recommends relatively small machines for kids, and some states have laws to enforce it. But many families ignore the advice because the small ATVs have less pizzazz and are quickly outgrown. Meanwhile, the industry's institute says that a minimum age (12) should be set only for those driving on public land. Many safety advocates like Rabe want much stricter age limits everywhere. The American Academy of Pediatrics, with 60,000 doctors as members, says flatly: "Children are not developmentally capable of operating these heavy, complex machines. ... No child under the age of 16 should drive or ride an ATV."

Studies show that states that prohibit young kids from driving ATVs see a reduction in serious injuries. Yet many ATV fans continue to resist such regulations. A few months ago, on Rabe's home turf, the Oregon Senate decided to eliminate a rule that says off-road motorcycle drivers must be at least 7. (That deregulation stalled in the House.)

Verdicts have been reached for three of the defendants in Diezel De Rupp's death. The parents of the 6-year-old driver pled guilty to misdemeanor child abuse in May. A judge found the third grownup not guilty because she was not a parent of either boy. Diezel's father, Jeremy Rupp, faces a trial on the felony charge in August. "Look within the cultural context where this occurred," says Rupp's lawyer, Charlie Fife, noting the popularity of ATVs in rural areas. "No matter where the line is drawn (on regulating ATVs), people are going to be hurt. It's better to leave it to the parents than to bureaucrats." That's the word from this branch of Western libertarianism.

"I haven't seen a single person here who thinks it's outright wrong to have kids on ATVs. They understand there's a risk. Everyone has grown up with it," says David Martinez, the Sterling Journal-Advocate reporter covering the trials. In the father's case, Martinez adds, a lot of people around Sterling believe that "the punishment has already been served."