[Tired of Taxes]

another anti-protectionist argument that I’ve heard that I find more plausible is that since our manufacturers use imported raw materials and finished goods to make the stuff they export, protectionism would have a negative effect on exports.

I think I probably didn't explain it well. What you typed above probably is closer to what the quote-unquote "experts" ;-) say. I try to back up everything with a source, but I only have a few minutes to type right now. I'll try to search for a source later.

[Tired of Taxes]

As promised, I found a source:

Today there are burgeoning domestic constituencies in numerous countries who favour lower tariffs because their livelihoods depend on access to imported raw materials, components, and capital equipment.... That dynamic is easier to appreciate when one considers that 55% of all US import value in 2007 consisted of raw materials, intermediate goods and capital equipment — the kinds of products the construction and manufacturing sectors purchase. Put in this light, it is more obvious that tariffs raise the costs of production, which undermines economic growth — or, as in the current case, economic recovery.

The article is here.