Edit: This turned out to be quite a long reply. I gave examples and background from Japan's warring states era of five or six of the top generals, and which ones wound up winning. I contrasted it with two arguably more courageous and smarter generals who weren't able to consolidate power after their victories and who didn't amount to much. It's a long comment with background and links - people who like Japan, strategy, or military history might enjoy this comment, though it turned out to be one of the longer ones I've written.

There's a lot of examples, but it can be hard to find them in recent history. If you're dealing with a country who has the same government or talking about a cultural icon, the tendency is to paint things black/white, good guys/bad guys.

And if one side completely annihilated the other? Well, then forget about trying to get a balanced perspective. Rome completely genocided and eliminated a highly advanced society called Carthage, but it's barely a footnote on history because there's no Carthaginian side to hear. On the flipside, since both the Nationalists and Communists in China survived WWII (Taiwan and Mainland), you can read pretty balanced perspectives on both places.

So that said, I'd recommend the Sengoku period of Japan if you want to learn about politics and military history. Its governmental policies are no longer in place and there were many sides keeping records. You can get a pretty good idea of what actually happened there and how the winners won.

Quick background, then I'll answer your question with a few specific examples of people and battles to read up on and give Wikipedia links as a jumping off point:

For most of its history, Japan had a dual power structure with the Emperor and the Shogun. The Emperor was literally God on Earth and in charge of everything. Nominally, the Shogun was the top servant of the Emperor and military commander, but the power went back and forth between them during different times.

Sengoku is when the Shogunate (the central military and earthly government) completely broke down and became powerless. Japan broke into basically a 30-sided civil war, with local lords commanding small armies and attacking each other.

There's three great unifiers from the Sengoku era - Oda Nobunaga, Toyotomi Hideyoshi, and Tokugawa Ieyasu. It's interesting that those three all came from the same camp: Hideyoshi rose from being a peasant to being one of Nobunaga's top generals and later successor. Ieyasu was close allies with Nobunaga.

These three men were probably not the most courageous, brilliant, or skillful of the Sengoku era. Notably, Takeda Shingen and Uesugi Kenshin were renowned for being amazing warriors and leaders. But Shingen and Kenshin got locked into a standstill battle with each other for years while Nobunaga swept through Japan conquering and assimilating people. There were lots of political marriages, and many times a father would be facing his son-in-law. Since the enemy side was frequently respectful and somewhat reverent to the enemy, often you could sign up their footsoldiers and lower ranked officers after defeating them (the higher ranked officers almost always committed ritual suicide when defeated).

Anyway, this is getting quite long, but here are some links:

The era itself (fascinating):

http://en.wikipedia.org/wiki/Sengoku

The three great unifiers:

http://en.wikipedia.org/wiki/Oda_Nobunaga

http://en.wikipedia.org/wiki/Toyotomi_Hideyoshi

http://en.wikipedia.org/wiki/Tokugawa_Ieyasu

These two were great generals and leaders, but got so caught up in fighting to a standstill instead of win/expand/recruit that their clans were later crushed (if you read deeply into Sengoku, you start to ask, "Why didn't Uesugi Kenshin accomplish more?" I believe the answer to this question is because he was fighting to a standstill, and not expanding upon his victories):

http://en.wikipedia.org/wiki/Uesugi_Kenshin#Uesugi_and_Taked...

Sengoku ended at the Battle of Sekigahara, the most important battle in Japanese history. It's considered the unification of Japan, and began a 250 year reign of almost complete peace and stability in Japan:

http://en.wikipedia.org/wiki/Sekigahara

Interesting note about Sekigahara - the battle was between Tokugawa Ieyasu (who won) and one of the top generals of the then-deceased Hideyoshi Toyotomi. That general's name was Mitsunari. Mitsunari was so generally offputting that that a number of lords, generals, and captains defected to Ieyasu's side because they disliked Mitsunari so much.

Here's the really crazy part - Ieyasu's men caught Mitsunari, and Ieyasu ordered them to let him go so he could lead the enemy troops. He knew that there were 2 or 3 generals that would potentially defect from Mitsunari's command. So in this case, it's almost the opposite war of recruiting - poison the enemy leadership and make yourself a more attractive camp. Ieyasu did really reward and take great care of everyone who came to his side - he didn't take much luxury for himself, instead setting his son up to rule and making everyone on his side wealthy.

One last one that should illustrative the point quite well:

The Battle of Okehazama is one of my personal favorite battles in history. It's how Nobunaga got started. A guy named Yoshimoto was taking 35,000 troops to go crush Nobunaga and take his lands. Nobunaga took 1,500 of his best troops, snuck around behind Yoshimoto's main force, and raided Yoshimoto's camp during a heavy rain, and killed Yoshimoto.

This battle set of the era - it's really amazing to read about, one of the greatest underdog stories in history.

http://en.wikipedia.org/wiki/Battle_of_Okehazama

"ad Nobunaga decided on a frontal assault, the battle would have been deceptively easy to predict; his army was outnumbered ten to one by the Imagawa forces. A frontal assault would be suicidal and an attempt to hold out at Zenshō-ji would only last a few days. Because of the odds against their side, some of Nobunaga's advisers even suggested a surrender. Nobunaga, however, decided to launch a surprise attack on the Imagawa camp."

"With their leader dead, and all but two of the senior officers killed, the remaining Imagawa officers joined Oda's army. Soon the Imagawa faction was no more and Oda Nobunaga was famous as his victory was hailed by many in Japan as miraculous. The most important of the samurai lords who joined Oda after this battle was Tokugawa Ieyasu from Mikawa Province. Tokugawa would remain a loyal ally of Oda from this time till Nobunaga's death."