You're straining at gnats, fakeit. "little, if any thing, was gained by the protection which the United States maintained in the first part of this [the nineteenth] century."
That means two things: either protection did so little for the industries as to be considered negligable or it did nothing at all. Seeing as either would constitute a failure for a policy that boldly claimed it was essential to industrial survival in those sectors, I'll let you take your pick: "protection did next to nothing good" or "protection did nothing good."
"If any" is NOT a firm statement that there was none either. There is little, if any, chance I will be shot and killed on the street but to you this means I definitely will NOT be.
You are artificially truncating Taussig's quote to alter it into an unrelated hypothetical. Taussig did not say "little if any" - he said "little, if any thing" - a 19th century spelling of what we use today in "anything."
Just because you want it to mean what you want it to mean doesn't mean that it means what you mean.
Print that one out, take it to the mirror, and repeat. You need it far more than I do as the above clearly demonstrates.
"little, if any thing, was gained by the protection which the United States maintained in the first part of this [the nineteenth] century."
The phrase if any thing is adding emphasis, not detracting.