It started out benign enough. In November 2008, California voters passed Proposition 1A, which authorized the issuance of $9.95 billion in general obligation bonds to fund the first stage of a high-speed rail link between Los Angeles and San Francisco, with extensions to San Diego and Sacramento. The project would cost $35.7 billion. The federal government would pick up a chunk. And it would be profitable.

High-speed rail works if it links big urban areas, has lots of riders, and covers medium distances so that travel times are shorter than driving or flying. The most successful is the Shinkansen between Tokyo and Osaka, which transports 150 million passengers per year. Even Amtrak’s slower route between New York City and Washington DC is profitable, though the rest of Amtrak is not.