Yemen has been a long time breeding ground for islamic terrorists. But, no worries, it's rulers know how to deal with that. How? Simple. They say the west in order to keep the terrorists away should send them money.
Sound familiar? Something along the lines of:"Pay me 5000$ a month and I will protect you from various mischief that might happen"? All similarity is purely intentional.
And what if the terrorists don't go away? Then Yemen will ask for more money. And most likely get it.