Immigration authoritarians -- including US president Donald Trump -- urge us to think of the "caravan" now trying to get its members across the gang turf line ("border") as an "invasion."
That's a very common argument from immigration authoritarians about immigration in general, and of course it's bullshit. Some guy trying to get from Juarez to Topeka to get a job plucking poultry isn't an "invader." Neither are 5,000 of them an "invasion." They're not looking for a fight and they're not trying to seize territory. They're doing the same thing you're doing if you travel from Nashville to New York (crossing numerous city, county, and state "borders" along the way) for a job interview.
But now Trump has used the "invasion" idiocy to justify stationing military forces at the turf line and having US "law enforcement" attack the immigrants.
Well, OK, then. Let's take him at his word, just for the sake of argument.
An "invasion" implies a war.
And using CS ("tear gas") is a war crime.
So, is it still an "invasion?"
If so, the United Nations needs to constitute a war crimes tribunal and demand the handover of the entire chain of command involved in this fiasco, up to and including Trump himself, to face the music. Under the Chemical Weapons Convention, to which the US is signatory, "[e]ach State Party undertakes not to use riot control agents as a method of warfare" (among other things (including not having those weapons in the first place).
Hey, don't complain, immigration authoritarian "invasion"-quackers. Words mean things.