No we can't know.
I am of the opinion that if powerful nutball leaders happen in nutball countries, a nuke might get thrown (which of course would be horrible). But the armed force of a million followers will not happen. Again China doesn't do it, too rich, too happy. Russia doesn't do it, nobody it could beat in a war and the people would never support it.
Many middle eastern countries have too few people and don't have multiple millions in their army...and those that do are surrounded by other Muslim countries with their own fanatics. They don't trust other middle eastern countries...and often they don't like those in their same country. And in the end were they amazingly able to get a force together...who do they invade? India? With a billion people, no. Russia? Ask the Germans/French about invading Russia. Africa? I'm not sure why they would invade Kenya. Europe? Ten times the economy and 100x the technology, no.
The rich are too rich for conventional war. The poor are incapable of it (except for terror and a throwing a nuke). That's the way I see it going forward.