Why does Gorudo fight Jowy?
Until that moment, Gorudo's actions mostly make sense. He doesn't want to be bound by the Jowston Alliance. He wants Matilda to be strong and independant, which is why he advocates neutrality. When Highland invades, he doesn't want to fight a battle he can't win, so he surrenders, and gets "independance" in exchange (in truth, he becomes little more than a vassal of Highland, but whatever).
Then, when Riou invades, he attacks and fatally wounds Nanami, prompting Riou and Jowy, both blinded by sorrow and anger, to retaliate. They beat him and he dies.
But why did he fight Jowy? I can't see why he wouldn't just back off. The leaders of the two opposing armies are allied against him. If he kills both of them, both armies will hate his guts (if they don't already). About half his men have already defected, so it's not like Matilda would suddenly become the most powerful nation.
Sure, he could frame Riou for Jowy's murder, and with Riou dead, how would he defend himself? (The other way around would be impossible, because there's no way Jowston would ally with him at that point). But (and that's not even going into the fact that Jowy obviously wouldn't have any tonfa wounds on his body), that would put Highland into a succession crisis. Good, one might think: they would be too occupied with their internal matters to interfere with anything Matilda-related, thus gaining him true independance. But then, no one would defend him against a Jowston retaliation. Sure, with Riou dead, they'd have no leader anymore, but they'd likely thirst for revenge. With still a master strategist in Shu, and political leaders such as Jess and Teresa, the first thing they would do would be to destroy Gorudo. Matilda is not that strong without Highland. The army would be much less unified, but I don't think it would fall apart overnight to the point where they can't attack Matilda.
Of course, Jowy actually attacked Gorudo, so one might say he simply fought in self-defense. But Gorudo actually should have refused to fight and get away, Jowy, being a pragmatic guy, would have calmed down eventually. Or either Leon or Culgan would have eventually made him realise that losing a useful ally for killing one girl who actually assaulted said ally's fortress is simply not worth it.
In the end, Gorudo had nothing to win by fighting Jowy, and pretty much everything to lose.
Am I missing something?
Gustav gained independance the smart way.
Sorry if my syntax is awkward, English is not my first language.