For those who skipped Econ 101 or took it before about 1990, we now live in an inextricably interconnected world of global supply chains. The finished component relies on parts from several global sources, and those parts, semiconductors and, yes, tubes, rely on another set of supply chains for the machinery to fabricate the components and a second supply chain for the silicon, tungsten, and rare earths necessary for their fabrication. Those sources in turn rely on the manufacturers of extractive mining equipment who rely on ... and on and on it goes. Those heady 19th century days when technology amounted to coal, iron, brass and wood, and economic self-sufficiency was a possibility are long gone and so is any relevance of tariffs based on that kind of economic theory. Driving with the rear-view mirror it's called. Not surprisingly, it ends up in a crash.