To be honest, this was a copy/paste job from another place I discussed the subject. I initiated it at the beginning of Trump's trade war, when many Trumpsters at that place were claiming they were going to be awesome. So that is what was meant by "why you think they'll work". It was a targeted request of people who actually think tariffs are effective. I personally do not.
Red:
TY for identifying what "works" means vis-a-vis the question you've posed.
The meaning you've identified, even though it's a paraphrasing of others', "Trumpsters," is not objectively measurable; there is no unequivocally defined bar that can be observed to have (or not), by the tariffs, been reached or exceeded. Instead, it's purely subjective.
- Examples of objective definitions of "works":
- The tariffs do/did measurable thing A.
The tariffs do/did measurable thing B.
The tariffs do/did measurable thing C.
Therefore, the tariffs work.
- The tariffs are structured "thusly" and in accordance with estimating model X, they are expected to yield "thus and such" outcome(s). If they yield that genre of outcome, +/- "XYZ quantity or rate," they can be said to have worked.
- Basic economic theory and tests of it indicate that tariffs increase producer surplus (PS), decrease consumer surplus (CS), create deadweight loss (DWL), and generate tax revenue (R). If as a result of tariff regimen ABC:
-- PS increases by X percent,
-- CS decreases by no more than Y percent, and
-- R exceeds DWL by Z or more,
I will deem tariff regimen ABC to have worked.
The gist of the above examples is that whatever "works" means, it must be something that when dispassionate and impassioned observers measure the tariffs' outcomes/performance, there can be no disagreement about whether have been or will be met the outcomes that define "works."
Obviously, "works'" definition must be something distinct to tariffs' possible outcomes, that is, the outcomes cannot be non-sequitur to what tariffs effect. For example, if "works" means the birth rate increases by X percent, that is a non-sequitur-to-tariffs outcome; thus even though that is a measurable quality, it's a definition that's no better than is a subjective definition.
Insofar as "works," as your question (or the Trumpsters whom you've described) defines it isn't a measurable I have no comment to offer on whether they work or will or won't work. I don't because I've already referenced
several sources of high quality theory and empirical analysis of tariffs, both in general and specifically. One can use the content in those documents to infer whether any given tariff augurs to, by one's own subjective definition of "works," works or will work.