On Tuesday, when President Obama tours the grim scene at the mudslide in Oso, Washington, where at least 39 people were swept to their death, he won't be able to do much more than comfort families of the victims and sign the disaster declaration that starts federal aid flowing to the tiny, shell-shocked community.

Preventing people from living in harm's way is a more complicated question, one not solved by a stroke of a presidential pen. The authority to restrict development in areas prone to risk lies with local and state zoning boards and building departments. But prohibitions on construction usually run headlong into property rights issues.

"There's your conundrum," says Lynn Highland, who heads the National Landslide Information Center at