There is no conservative argument for protectionism. If there were, someone would have stated it on this thread already.
...from a conservative perspective, just exactly what is wrong with saying we need a certain minimum amount of manufacturing capability in the United States for national defense purposes?
If you can state rationally why this is so and what the percentage is then do so. If you can't then there's your answer.
Just exactly what is wrong with specifying that the federal government will give preference to bidders based in the United States?
We are not discussing federal purchasing. We are discussing federal subsidies to certain American companies regardless of who buys their products. The fact that you can't follow the discussion should tell you something important.
Since the country was funded with tariffs the first 80 years of existence then by your distorted reasoning the founders were liberal. LOL.