Machine guns are pretty handy for guerilla warfare.

Tanks, not so much.

That was just an example. Others include:

* helicopters

* jet airplanes

* satellites

* artillery

* light armored vehicles

* unmanned drones

etc.

As a side note, I fucking hate HN's formatting.

With or without all those weapons, an ethnic cleansing operation becomes markedly more difficult when the local population all have assault weapons and training in how to use them...

The US military has all of those things and yet the Iraqi resistance still put up a good fight.

Because the coalition forces in Iraq aren't engaged in ethnic cleansing. If they weren't worried about killing civilians and looking bad on the news, they could probably level most of the country.