So the answer is the same as any war: you make it too expensive to keep fighting. It's the same reason a bunch of barely trained people in the desert won a war against a force with far greater military power. It's the same reason a bunch of jungle people defeated the country that just won a world war. It's also the same reason a bunch of rednecks defeated the largest military in the world (at the time) and were able to create an even larger empire.
It's not hard to make them give up. It's going to be a cat and mouse game but it already is