[Goose]

If a country were to shoot down a Russian missile while the missile was traveling over Ukrainian territory en route to killing Ukrainian people, that would be considered an aggressive/instigating act against Russia? 

I understand that laws are often counterintuitive, but that really seems backwards.

Russia would certainly consider it so. In point of fact, shooting down/destroying any nations "property" over territory that is not yours is arguably classifiable as an act of war. Replace missile with ship and I think that is pretty clear. If you are taking overt military action to defend another nation you are de-facto an ally of that nation and actively participating in the war. Selling or giving weapons to Ukraine doesn't make you an "ally". Actively participating to defend Ukraine does.

In any case it doesn't matter what the "letter of the law" may be. Russia would say it was an act of war by Poland and the other NATO nations aren't going to go to war with Russia because Poland did something they absolutely knew would draw that response.

[Goose]

If a country were to shoot down a Russian missile while the missile was traveling over Ukrainian territory en route to killing Ukrainian people, that would be considered an aggressive/instigating act against Russia? 

I understand that laws are often counterintuitive, but that really seems backwards.

Russia would certainly consider it so. In point of fact, shooting down/destroying any nations "property" over territory that is not yours is arguably classifiable as an act of war. Replace missile with ship and I think that is pretty clear. If you are taking overt military action to defend another nation you are de-facto an ally of that nation and actively participating in the war. Selling or giving weapons to Ukraine doesn't make you an "ally". Actively participating to defend Ukraine does.

In any case it doesn't matter what the "letter of the law" may be. Russia would say it was an act of war by Poland and the other NATO nations aren't going to go to war with Russia because Poland did something they absolutely knew would draw that response.