Self defense of the economy is different from self defense of an imminent threat. An imminent threat you have the innate right of defending yourself. Economic terrorism probably isn't an imminent threat if you're referring to economic hardship. Literal terrorism is another discussion.
Imperialism is self defense of the economy. Invading a foreign country for oil is self defense of the economy. None of these are justifiable.
This is taking self defense too literally but to some American politicians I'm sure this falls under self defense of the economy. Self defense at the expense of others.