Re: @Pete 2 - wolf in sheeps clothing
Russia still has not delivered a declaration of war despite it lasting 3 months already.
Formal declarations of war have fallen out of favour for various reasons.
The reason that Pearl Harbour was considered a day of infamy was that Japan hadn't given some kind of formal last warning and were still in negotiations with the US. Plus of course, they attacked us.
In the case of the Falkland Islands conflict (note not war), again Argentina were in negotiations over sovereignty and then launched a surprise attack. Whereas Britain gave them a deadline when if negotiations hadn't achieved them leaving the islands again, we would feel free to do bad things. So they didn't declare war because they were being sneaky. We didn't declare war because we had the limited objective of removing Argentinian forces from the islands and weren't planning to do anything further after that.
Putin is somewhere in the middle. I'm pretty sure he made a public statement just before the invasion actually happened, so it wasn't a sneak attack. And he'd obviously made threats and attempted to negotiate, though from Russian demands most anaysts I've read believe that the demands were just for show, the decision to have a war had already been made - and the demands were designed to be rejected. They weren't even designed to be a maximalist first offer, to be negotiated down later.
Obviously the ideal is that country A says to country B - you're doing this thing that annoys me. Stop. Or else! They have a bit of a negotiate, to no effect. So country A says, I'm setting a deadline, and if you've not given me stuff by then - then I really mean "or else"! Which obviously gives country B the chance to back down, knowing country A really means it. After said deadline you then get a declaration of war.
However war is a bit maximalist and requires a peace to be agreed by both sides. If the objective is limited in some way, you might not want to declare war. Say in the Falkands, we didn't attack Argentina. Or their interests around the world, we simply made an exclusion zone around the Falkands and said we'll kill anything in that and reserve the right to kill anything threatening it. So we did hunt down the Argentinian aircraft carrier, for example, which never even entered the exclusion zone. But we didn't attack Argentinian coastal shipping, or their airbases - from which they were launching attacks on our ships. Also their carrier went back into territorial waters to hide, and the British government ordered the submarine tracking it not to follow, or to attack it while there. So the amount of violence was quite calibrated. The other advantage of not declaring war here being, that once you've recaptured the islands, there's no need for a peace conference, which the Argentinian junta might have refused to take part in. Leaving us in a formal state of war for who knows how long, as North and South Korea are still stuck in - they've only signed a ceasefire.
Hence the whine above about Grenada. Who would the US and the RSS (Carribbean Regional Security treaty countries) have declared war on? Grenada's legitimate government had been overthrown in a coup - so they were going in to restore it. They did so (it wasn't just the US), and then left. Therefore they couldn't declare war on Grenada - and they didn't recognise the legitimacy of the coup regime, so they would have been declaring war on the very government they recognised and were going in to restore.
The alternative would be to declare war on Cuba, who had sent troops in to back the new regime. But why do that when you don't want a war with Cuba. Kick their troops out and they'll get the message just as well. And with the old government restored, there's nothing left to fight over.