White on Powder Blue makes an easy target in an urban environment, even better when ya get in the boonies.
Why is this a reoccurring meme, btw?
There's literally zero chance of "UN troops" invading. First off, the UN has zero troops. None, nodda. They occasionally have police but it's on a per country basis. UNMIK for example had police, and they were limited to very specific things. Mostly providing protection for officials because the local cops weren't exactly neutral or trustworthy. The UN has to ask for troops, and countries have to provide them. The original country still owns their troops. There may be a "UN commander", but they're still just XYZ country's officer that is nominally in charge of other countries' units by agreement. Zero difference from our NATO, non-NATO, non-UN or joint operations.
Not many foreign troops would voluntarily invade America. Actually, none aside from Russia or China. Only countries that essentially would be willing to shoot their own troops to maintain discipline COULD even land. That rules out most of the world. This isn't academic. I've discussed it with foreign troops/cops. To the last man, none would volunteer for occupation and virtually all of them would mutiny.
Secondly, said countries have to be willing to accept massive casualties. Which also rules out most of the world.
Third, they have to have the resources to fight a country of 300 plus million. Which rules out most of the world.
It's completely stupid, and yet persistently enduring, conspiracy theory. So, I'm actually curious. Besides "I don't like them, so they're capable of any evil I can imagine", why does that meme survive?