Can this be circumvented if it got sent to Australia first and from there to the States? Obviously, there is an additional cost. Or is Australia going to get hammered with 145% tariffs?
Yes, but it's essentially fraud. The common term is "Origin washing." You have to declare the origin of the shipment, and the exception is that it goes through "substantial transformation."
If you were to buy a bunch of components from China, have them shipped to Australia and assembled there, then shipped to the US, you would pay the tariff applied to Australia, not China. Of course, you probably are paying some sort of import tax when the components make their way into Australia too.
On the customs form, you're supposed to specify "country of origin". Tariffs are based on where the item was created, not just where it went in the mail box. Things get more complicated when they are built with parts from various countries.
