Back in 2012, the Obama administration levied tariffs on solar panels from China, to punish the country for unfairly subsidizing its panels in an attempt to corner the market. In the ensuing years, US imports from China fell off sharply and imports from Cambodia, Malaysia, Thailand, and Vietnam rose just as quickly.

Early this year, a tiny California-based solar manufacturer, Auxin, filed a trade complaint with the US Department of Commerce, alleging that China is effectively laundering its solar supply chain through third-party countries, thereby illegally circumventing tariffs. It asked Commerce to apply commensurate tariffs on imports from those countries. (Canary Media has extremely thorough coverage of the case, if you want to catch up.)

Commerce is investigating. Meanwhile, the industry has been thrown for a loop — imports have fallen off, projects are being cancelled, and projections of growth are being revised radically downward. The tariffs could be anywhere from 30 to 250 percent, which would radically change the economics of big solar projects, and if applied, will be retrospective over the past two years, which means even existing contracts are in jeopardy. The uncertainty has cast a pall over the entire sector.

The Solar Energy Industries Association (SEIA) has been advocating against tariffs from the beginning and is calling on Commerce to dismiss the complaint. I contacted Abigail Hopper, the head of SEIA, to talk about the merits of the case, whether building a domestic solar supply chain is a good goal, whether tariffs work, and what other policies might be preferable.