Having a war with Mexico is not even a remote good idea, having the us border compromised is a very dangerous strategy, even if Mexico doesn't have the military resources to damage the US, they can ally with any other country that can nuke U.S., like ie, north Korea, also, you should consider the incredible high amount of Mexicans living in the us, what would they do as soon as they realize their families are dying? The amount of terrorism will be out the charts. Mexico have a lot of ways to get in the USA most of the border patrol officers are latinamericans, trust me, I live in the border, Mexico narcotrafficantes have hundreds of tunnels made for drug traffic, they can be used for war purposes too. Having a war with Mexico is the worst idea ever, but bottomline, why would they nuke Mexico, and spend hundreds of billions going to this war. Oil? Is not worth, Mexico is a giant landscape impossible to colonize by USA, maybe they can set some kind of trade agreements that benefit the us, but they don't need to nuke Mexico in order to obtain something like that.
A war is not proficient with Mexico, trying to insult and humiliate Mexicans is also a very bad idea for americans, and I hope trump stops this nonsense to Mexico soon, before Mexican stupid president starts the war himself to USA.