Do Libertarians support the tariffs or believe they are in any way a credible means to reverse the decline of US wealth and power?
I don't speak for the Libertarian party (uppercase) so who knows... but no, generally tariffs are anti-economic/obviously pareto inefficient.
We'll see what it achieves it terms of geopol negotiation cloud and/or lowering world prices via Optimal Tariff Theory
Seems likely in geopol terms to push other nations closer together.
Already China claims to be working with Japan and S.Korea on how to respond to the latest tariffs.
Europe and China with Japan, S.Korea and the rest of S.E. Asia now have more to gain by increasing trade between themselves and US ends up isolated and irrelevant.
China could further advance trade payments denominated in Yuan/mBrigde protocol and the USD loses its trade payments predominance, costing USA one of its last significant strategic advantages.
'Optimal Tariff Theory'?? Tariffs never lower prices!