“Did you know that Indonesia is at a crossroads? It is!” So said Homer Simpson, flipping vacuously through the Economist. But this is no joke: a ban on exports of unprocessed ore in January really could put Indonesia’s economy in a tricky place. The ban, aimed at building a local processing industry, is a bad idea when foreign investors are already getting spooked. The rupiah fell by a fifth against the US dollar in 2013. And the Federal Reserve is tapering.

The ban might seem like a terribly good idea to investors long nickel – the worst-performing base metal of 2013 because of excess supply. The nickel price, down by a fifth this year to $14,000 a tonne or so, is now below its marginal cost of production. Indonesia is the world’s biggest nickel producer. Time for a rebound on the back of the ban?

Not quite. First, the ban’s actual hit to Indonesian production could be less than total if international miners exploit a loophole that lets them export ore if they smelt the stuff first. Both Rusal and Glencore have beaten a path to Jakarta with blueprints for smelters; they have more knowhow than locals. An ironic outcome, given the ban’s aims.