One of the last bastions of defence for the advocates of protectionist policy is the old "infant industry" argument.
I am well aware of the many theorical arguments against this argument but despite this, the protagonists point to such examples as South Korea and Japan that appear to have very successfully fostered and protected modern industries through strong state intervention in the economy. It is very hard to argue that this kind of rapid development that these countries experienced from the 60's to the 80's would have taken place in the absense of the various government programmes aimed at their promotion.
It is notable that both of these countries were recipients of large amounts of US aid after their respective wars but it does seem to be their protectionist policies that enabled them to develop and end their reliance on aid.
Can it really be argued that their policies failed? That their apparent success was despite these policies and not because of them? That they would have seen such rapid capitalisation and modernisation in the absense of protectionist policies?
When considering whether to adopt a protectionist policy with the intention of fostering an "infant industry", a government will concern itself only with the wellbeing of it's own people.
Which only makes much sense if they're not part of an integrated market. If they're not, they'll suffer in other ways (e.g. less access to a wide variety of goods, capital wasted on the subsidized, subcompetitive industry, no competition from abroad &c.)
Freedom of markets is positively correlated with the degree of evolution in any society...