In-country wars were what made America the US of A. Fight the inhabitants, claim their land, profit. Great example of a great nation, huh?
Korea was not an EU operation. South Korea and US were the main combat force, UK had about 15k troops (over 300k US troops). So it was not an EU failure as they did not have command, the US did. The support groups were not at the front line all the time (if at all).
As for 'Nam, the US did the same the French tried before. So they basically did not learn a bit from their fiasco. Bombing runs were not successfull in WW2 nor were they in Vietnam. The Vietcong and NVA had tunnels that were bomb proof. They just crawled deep into their caves, drank tea, listend to Uncle Ho and waited for the end of the Arclight raids. After the last bomb detonated, they simply crawled back out and did what they were before as nothing had happend. Read some first hand experience of MAC SOG, SEALs and LLRPs that did the BDA after such B-52 runs. The US murdered the farmers instead of helping them fight the VC. You donāt expect them to help the US/South when you just throw napalm on their huts?
The Russians were beat in Astan because of the USA. Now the USA has to deal with the very Taliban they let rise to power after the soviets retreated. Same mistake all over again, nothing learned from Vietnam or Korea.
The issue with foreign wars is that the peple definding their nation have something to lose. The common GI only does what his superior tells him. In WW2 there was a omnipresent threat to the world, so they fought with dedication. In Astan and Iraq most soldiers only do what they are told, not because they feel it is right to dabble in foreign politics.
Britian is involved in most US interventions, of course they have to say there are WMD, otherwise the people would not support the war at all.
And whoever thought you can win in Iraq or ASTAN is blind and dumb. You can not win a guerilla war as long as one fighter is alive. And asymmetic warfare can not be won, there is no frontline, no indication how many are still active. The IRA simply ceased to openly act against the government, they still exist.
The Iraqi soldiers are only as good as the ones teaching. While in WW2 the avarage soldier could actually shoot, the soldier in Vietnam was unable to hit at 25m. With the modern fully automatic weapons, precision was not deemed necessary, a wall of lead was the new ātacticā. Same as carpet bombing. Simply does not work as one well placed shot.
So basically you can look at history and see that war does not work when the people are not into the cause. Look at foreign wars in the past. Only WW2 was a success and directly lead to war against communism, so not really world peace.