I'm interested. You can email me if you want...
I'll keep it limited to thoughts and ideas that we could apply to our own settings. But basically, the reason one country supports another often has more to do with who the enemy is than who the country your supporting is.
Supporting a friendly neighboring country is, in the political realm, almost a no brainer. If you aren't supporting them, it's because you are planning to take them over yourself (which you could more easily do by supporting them, like I said, no brainer).
By supporting the friendly neighbor, you keep the friendship alive. Good trade, good relations, etc. But much, much more importantly, you get to fight a war in his backyard, not your own. All the collateral damage is being done to his country, not yours. In the end, you help his country out, in exchange for very favorable trading rights.
Also, you are protecting your future, because the enemy he is fighting today, could very well be the enemy you are going to fight tomorrow if he isn't stopped today.
But often a country will find reasons to support another country even when they aren't neighbors and aren't close to each other, and why? Because you are supporting them against your enemy.
You don't even have to like their country to help them against your enemy. In fact, historically, this is often the case. You are most likely helping the other country because by doing so, you force your enemy to expend more resources and more troops. Bad for their economy, their morale and their bloodlust.
I can email you specific historical examples of this...both recent and old if you want. But if you think about it, I'm sure you'll come up with a lot of them (many recent and high profile).
Cedric