Well, I surely don't have a good handle on economics or international affairs, but in the short term, the tariffs seem pretty idiotic. I work for a USA based power supply company with a manufacturing arm in Suzhou, China. I think it's not that the US is incapable of producing a power supply domestically, but rather that the USA can't compete with the incredible manufacturing supply chain that has developed in China over the last 20-30 years. So, to think slapping a 25% tariff is suddenly going to bring home manufacturing, is ignoring the global manufacturing supply chain that exists today. Literally, there is no other place in the world (and definitely not the US) where every part of the manufacturing process can be found within a 15 minute drive of each other. It's not that it couldn't exist in the US. It's just that it currently doesn't so you're not helping much, in that respect.
All that aside,
The US likes to think of itself as a (once) manufacturing superpower. And it was. But, I think that that this fondly remembered era was probably made possible by a number of international events that kind of made it the world's manufacturing center, by default. Post WWII, etc.
I suppose by the time the 80s and 90s came around, some other countries had improved their infrastructure enough that they could produce USA-built equivalents for less. So, US companies were forced to either offshore or cut their margins. I suppose most companies decided to offshore because who likes thinner margins???
Some of it I feel was just plain corporate greed. I understand that companies need to stay "competitive" but I feel that it is sometimes used as an excuse to fatten up the bottom-line for the shareholders. Did Keithley really need to move manufacturing to China? (I don't know; I'm not a business person.) But from my perspective, no, they didn't. They had a limited product line, probably a very focused R&D effort, and were likely still quite profitable (based on the price of their stuff).
So, I'm really not an offshoring sympathizer. I think it would be great if American companies looked out for Americans more. (At the same time, I'm happy that Chinese and Taiwanese and Indian people are employed.) But at the same time, I feel that it is almost your unwritten duty as a US company to at least not completely screw the people of the country you represent.