I believe that US taxpayers money for economic stimuli should be spent on US products, but realisticly that is hard to enforce. There are many foreign made parts in US products and US parts in foreign products. I think it should be modified to buy US first, and if the US sources are tanked out, then augment it with foreign sources. Example there are very little US steel mills left, and they would not be able to provide all the steel needed for any major construction program. So if the production is maxed out, open it to foreign sources. I think the most important part of the stimulus program is mandate vendors to hire American only. Ironicly the Dems oppose this in order to cater their Hispanic constituents. The GOP needs to exploit this issue, and many blue dog Dems will joint thm in this endeavor.
You make a good point about Hire Americans Only.
Capitalism works best when everyone is doing it. Protectionism hurts everyone.