Ahead of America’s election in November, company bosses, financiers and diplomats are busy calling on Donald Trump’s allies, trying to divine the economic policies that the former president will pursue if he is re-elected. But there is one man in Mr Trump’s orbit who holds more sway than most and who, for now, is virtually inaccessible. That is because he is inmate number 04370-510 in the Federal Correctional Institution of Miami.

Peter Navarro, a leading economic adviser in Mr Trump’s first administration, is more than halfway through a four-month sentence for contempt of Congress. He bristles with indignation at the justice system, disdains Joe Biden’s record and longs to steer America towards hardline protectionism. In written correspondence with The Economist, Mr Navarro has laid out how he thinks Mr Trump should approach trade—from turning up the heat on China to slapping tariffs on just about everyone else. It is a dark, angry vision for the global economy. As polls stand, it is one Mr Navarro may shortly be able to promote from inside the White House.