I think he's literally in the process of invading and subjugating a neighbor, actually. The Saudis might not call what's going on in Yemen an invasion, but it sure looks like it from here.
Yemen and the treatment of Khashoggi and many others by the Saudi govt could eventually yield a case for helping their neighbors resist them. Yemen is pretty horrible. We are stuck with oil dependence for now.
Yes, but it's a global market and there is not a barrier to oil at our border. SA increasing or decreasing world oil supplies affects the oil prices here. There's a separate discussion about the refineries in the US affecting the price of gas at the pump much more than the price of the oil. But let's focus on the fact that SA can increase or decrease the price of oil form them, it's a world wide commodity, and their actions affect the price people pay for oil in the us, because it's a world wide commodity.