The WSJ profiles how the U.S. electricity grid is vulnerable to attacks on its transformers, which are the "glue" that holds the network together.
Few companies make transformers in the U.S., and the equipment can take over a year to produce and months to ship.
An assault on enough of the country's biggest 2,000 transformers could cause extended blackouts. Last year, a gun attack on 17 large PG&E Corp transformers took a California substation off line.
"With a couple dollar bullets, you can take out a transformer worth millions of dollars," said Steve Newman, vice president of Delta Star, a supplier of the products.