Except tarrifs rarely help any of that: there's already extensive regulations in place to require local sourcing for defence critical components, all the way down the supply chain.
And tarriffing imports doesn't make a difference in the case of something like shipbuilding where the real problem is the government hasn't got a consistent order-book to keep factories staffed, operating and training - nor a plan to allow that capacity to leverage into being self supporting.
Like a much better plan has always been defence exports: increase your customer base to spread risk and reduce per unit prices. The F-35 and it's adoption was a great idea in this regard...right up till the US started threatening NATO allies and cutting off avionics support to partner nations (Ukraine) in the middle of a war.
You don't get a defence manufacturing industry without actually paying for a defence manufacturing industry. The whole "bring manufacturing back" idea is almost wholly disconnected from it: a ton of factories extruding plastic childrens roys aren't suddenly going to start making anti-shipping missiles - in fact this is related to a secondary problem which is that it's not remotely clear that a peer/near-peer conflict would look anything like the long wars that WW2 represented due tot he delivery timelines on advanced weapons systems. You basically go to war with the military you have.
And tarriffing imports doesn't make a difference in the case of something like shipbuilding where the real problem is the government hasn't got a consistent order-book to keep factories staffed, operating and training - nor a plan to allow that capacity to leverage into being self supporting.
Like a much better plan has always been defence exports: increase your customer base to spread risk and reduce per unit prices. The F-35 and it's adoption was a great idea in this regard...right up till the US started threatening NATO allies and cutting off avionics support to partner nations (Ukraine) in the middle of a war.
You don't get a defence manufacturing industry without actually paying for a defence manufacturing industry. The whole "bring manufacturing back" idea is almost wholly disconnected from it: a ton of factories extruding plastic childrens roys aren't suddenly going to start making anti-shipping missiles - in fact this is related to a secondary problem which is that it's not remotely clear that a peer/near-peer conflict would look anything like the long wars that WW2 represented due tot he delivery timelines on advanced weapons systems. You basically go to war with the military you have.