Are trade wars good (and for whom)?

Recent news has made it plain that President Trump intends on going through with his much discussed plan of implementing tariffs on many sources of steel and aluminum imports to the US. This seem as good a time as any to ask a question that begs for evidence: Are trade wars good, and who benefits?

There is good reporting out there that analyzes the likely impact of this particular steel tariff, so feel free to find it and use it in your own argument (there are figures the administration has produced and figures that other studies have produced using the same source material). There are also plenty of other tariffs out there throughout history that have been studied and discussed. Because these sources can sometimes conflict, please be aware that your choice of what sources to use may need to be justified.