For the past year, everyone has had an opinion on the Russia-Ukraine conflict. Some say it is a regional conflict, while others say that the invasion can be considered the start of World War III. NATO countries are openly providing bigger and bigger weapons to Ukraine, and other Russian allies such as Belarus may join the fight soon.

Considering past world wars, what conditions need to be met before a world war is declared, or when would we know for sure we are in one, other than nuclear weapons falling on our heads?

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    I’m voting to close this question because there is no "definition" of world war, these are just names that get attached to particular conflicts. And the WW1, in particular, was not a world war in a literal sense. There is no answer, and nothing to be gained by further discussion of current conflicts in Europe in relation to this question.
    – James K
    Jan 22 at 7:20
  • At the very least, this is a History question. For one thing, the only way to answer it is by going over when "The Great War" and WWII was so named. For the other, it's not like as if anything is triggered if some official body declares a WorldWar. Jan 22 at 7:33
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    In fact, according to some, the first "World War" was the Seven Years War, so by this account WW3 did already happen.
    – SJuan76
    Jan 22 at 8:40
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    Poor prior research and rather off-topic here too.
    – Fizz
    Jan 22 at 9:55
  • How can we know if something is the start of an event that hasn't happened yet? As of right now that conflict is still very limited in scope compared to a lot of other wars especially the ones known as world wars. Until such time as a larger conflict breaks out or the current conflict ends this can't be answered.
    – Joe W
    Jan 22 at 15:34

1 Answer 1


The world wars were called so because, simply put, they involved fighting all over the world. This was much easier to each in WWI because of massive colonial empires in large alliances. In the second world war, the colonialism aspect was still in effect, but several smaller wars were joined into one when alliances became more solid.

Obviously, two countries fighting (and there are pretty much always two countries fighting) is not a world war. NATO countries providing weapons to a another country fighting a war is business as usual for the past 70 years. This is why it was called a "cold war", as it's a series of proxy conflicts by larger powers basically playing war games with other people's countries instead of their own. E.g. The Chinese civil war, the Korean civil war, the Vietnam civil war, the Syrian civil war, etc. Large powers arm one side of a conflict to test out new weapons and tactics without committing their own soldiers (which some exceptions, like Vietnam).

Nukes are not necessary for the world to be at war (nukes were sparsely used in war so it's a rather poor indicator statistically). The usual harbinger is a sign of a broken trade network. This can be seen after the fact in both world wars. A second indicator is, obviously, most countries in the world are fully mobilized (in a state of war). Right now, Russia isn't even fully mobilized which means that they don't seem to be treating the invasion of Ukraine very seriously, which is evident based on weapons used, various tactics, and their willingness to retreat from positions. A final indicator would be that countries enter a state of total war. Total war is basically the transition from fighting armies to razing cities. All three of these indicators were present for both of the previous world wars so they are likely good indicators for a future one.

I'd also reiterate the first point: a war across Europe is not a world war. Since time immemorial, there have always been wars stretching across the continent, from the Roman Republic, to Genghis Khan, to the Thirty Years War, to Napoléon. Each of these conflicts were ultimately, localized to a single continent with a handful of solvent and sovereign countries, not most of the world's countries on each continent.

  • I would call the Napoleonic war a world war in the same sense as WWI (but not WWII),
    – o.m.
    Jan 22 at 7:33
  • The Napoleonic wars saw extensive fighting in Europe, North America, the middle East, and smaller engagements in North Africa, the Indian Ocean, and South America. World War Two had very little action in the Americas, so you can debate which was more worldwide.
    – Stuart F
    Jan 22 at 11:54
  • Two uses of a weapon in a single war when only one country was known to have them makes them "sparsely used in war"?
    – Joe W
    Jan 22 at 15:22
  • @Stuartf the 7 years war (1756-1763) was far more extensive than Napoleon in terms of where it was fought, but the criterion is that most of the world's countries participate.
    – uberhaxed
    Jan 22 at 23:53

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