grammar - Why is it である not にある in this sentence?

Today I saw this sentence: イラクで戦争がある。

I didn't understand why that would be the case instead of イラクに because if it is で I feel like it could be rewritten:

戦争はイラクである。 which just sounds like Iraq is war.

Is there a reason for this? Is it an expression or something like that, can it be rewritten the way I wrote it and if so could you say 戦争はイラクです?

Thanks for your help

Answer

イラクで戦争がある。≒ イラクで戦争が起こる。

The ある means [起]{お}こる, [発生]{はっせい}する, [行]{おこな}われる (meaning #12 in goo辞書)
Compare:

イラクにXXがある。(= There's XX in Iraq.)
イラクでXXがある。(= XX occurs/takes place/will be held in Iraq.)

---

Edit

戦争はイラクである。doesn't sound very natural but would mean "The war will take place in Iraq" as a response to 戦争はどこであるんだ？(Where will the war take place?). It can't be interpreted as "The war is Iraq" nor rewritten as 戦争はイラクです.

"how would you differentiate the である that shows what something is and the である that shows where something is"
＞＞＞
I think it's all up to the context.

XXが/はYYである。

If you said 僕の故郷は京都である, then I'd interpret it as "My hometown is Kyoto". If you said 今度の会議は京都である, then I'd interpret it as "We'll have the next meeting in Kyoto".