Geez, I'm glad you're not war minister. It's a Chinese registered ship with a Russian captain.
If a terrorist crashes a truck with Portuguese plates into the US embassy in Berlin, would that mean Portugal's declared war against the USA?
I happened to notice that at least in some cases, the change of terminology happened roughly when it became clear that offensive war was a losing proposition in terms of money and resources. I suspect that as invading the neighbours became financially irrational, the cool heads that tend to survive in management shifted their stand from mixed offense/defense to just defense.
A few years later it was clear that offense was necessarily a resource loss. Someone who wanted to build a career as a civil servant might then see a defense ministry as a viable option, but not any sort of offensive war. Offense was clearly not viable, and therefore not a good basis for budget allocations, and therefore the good career move for the civil servants was to focus the ministries entirely on defense.