From European bureaucrats to Chinese authoritarian technocrats. Are they are all just idiots?
Professional academic economists are also pretty uniformly against tariffs. I am much more inclined to believe the academics over the bureaucrats and politicians, especially when the latter face political constraints much more restrictive than economists.
Also, as someone who has to teach undergraduates this stuff, the amount of people who graduate with an undergraduate degree in economics but don't understand the logic of free trade is shocking. A lot of these students go onto the public sector as well, so don't be so confident in the knowledge of those in authority.
No less than Paul Krugman of the NYT admits that, "[a] dirty little secret of standard trade theory is that big countries with substantial market power actually can gain from modest tariffs... Each country has a unilateral incentive to impose tariffs..."
The truth is that sometimes unilateral tariffs really do garner advantage, which is exactly why so many countries use them when they can get away with it. And yes, this advantage DOES come at the expense of others, and the net effect globally is pretty much definitely negative, so it would certainly be better from a global perspective if everyone agreed to no tariffs.
This has been known since the 19th century, large economies who can affect their terms of trade can institute an optimal tariff that leaves them better off than under free trade. The key assumptions are: the economy is large enough to affect world prices (probably holds for the US, China and the EU, but not for every other country) and that they don't face retaliations (seems unlikely given recent events).
It really is basically a prisoner's dilemma - but not really, since everyone can communicate.
People can communicate in a prisoner's dilemma as well. It just doesn't make a difference.
A lot of this comment is Yes, we have noticed the skulls.