Nearly a century ago, America embarked on a great social experiment in the Pacific Northwest, charging up the Columbia River and erecting dams.

It worked. Construction jobs pulled the country out of the Great Depression. Cheap electricity spurred the growth of cities like Seattle, Portland and Boise. And hydropower fueled the military effort to defeat the spread of fascism in World War II.

Now the system is buckling.

The Bonneville Power Administration, the independent federal agency that sells the electricity produced by the dams, is careening toward a financial cliff.