I've never been a fan of legislated/mandated protectionism, BUT I am a fan of buying local when possible as it definitely has a huge impact.
Instead of being legislated, I think retailers and consumers should be given informed choices of what they can buy, not just be presented by default the least cost option.
For example, if a retailer were to comparatively offer a widget made locally side-by-side with a similar widget made overseas, and make a point to market the higher quality(perhaps) and local impact the domestic product has, I'd bet some buyers would be willing to pay a little more for the local product. And for those that still want/need to shop driven purely by lowest price, then can buy the cheaper imported widget. THAT is the American way
The problem I see is that certain big box retailers have driven the American public to choose based purely on low price alone, and only offer the one CHEAPEST widget, such that the customer service, quality, and local impact part of the equation has been ignored... much to our communal loss. If people are instead given the choice, and educated on the impact that choice has, I think we could see some buyers choose local without being forced to by legislation.
And I do agree that protectionist legislation is a risky proposition. It didn't work prior to the Great Depression, and in fact worsened the situation as our trading partners retaliated. That could happen again.
Interestingly a certain big box retailer made a huge marketing push back in the late 80s and through the early 90s about "Made in America". They had price toppers, banners, etc. proclaiming their support of American products. But then sometime in the 90s it just changed, almost overnight, and was all import and low-price driven. The "Made in America" mantra was never heard again. Isn't that interesting??
BTW, as an aside, having been a Pittsburgh resident for many years, it is important perhaps to note that the steel industry has been part of Pittburgh's(and regional) history for a long time now. Although steel continued to be made, and is still made in some areas, that industry went into decline over 25 years ago. It's a shame on the one hand, but is also just part of the evolution of an industry and a region. Regional economies must always look ahead for new opportunities as their local economies will change over time. To rely on one industry permanently being supreme is a doomed proposition, almost by definition. That being said, Pittsburgh itself has reinvented its economy into many prosperous areas. So today it is perhaps less known for being the "center" of any one industry, but has several other healthy diversified economies, which is much healthier and robust than relying on one big industry. Pittsburgh still has its challenges, but I think is actually a model city on how to recover from losing a primary industry and reinventing itself.
Al