The League of Nations was a pathetic organization that did nothing to prevent WW2, and is pretty much seen now as what not do if you're designing an organization of that sort.
What not to do is designing a league and afterwards not joining the league, that is what not to do. It is very easy to look back and be judging, but it is another story to try to see the things as they saw it.
Hitler, threat
Stalin, threat
What to do, can't fight both. Ever heard of the enemy of my enemy is my friend? Didn't the US do it again with the Mudjahedin, members of Taliban in Afghanistan? When the Sovjet Union invaded Afghanistan, the US supported the Mudjahedin. that is what world politics is all about, opportunism.
Being proud of your country is ok, but remember that it is also a weakness. Pride is the stronghold of fools (as we say it in Holland), because it can blind you for things. You always need to stay alert, always need to stay critical towards your own country. Things can occur without you knowing it.
It is also a potential weakness. For example, americans tend to express their pride in symbols. The US flag, the Capitol, all these symbols that play a major role in your tradition. NK send me an email with a new ship last year made of the scraps from the WTC. US wants to show that they cannot be hurt and that they will never surrender to the threat of terrorism. Which is great, but it means that if you want to hurt the US, you go for the symbols.
If someone burns a dutch flag, the typical reaction would be: a waste of money (he, we're dutch) and we hope that he burns his fingers. If a US flag is burned, the impression I get is that a lot of people in the US are hurt to the bottom of their harts. That way it is easy to upset the US and we are all witnesses of what that can lead to: unsuccesful invasion of Afghanistan with some, tragically payed for victories. Same for Irak.
Being huble is -imho- the way to go. We are shown on a daily base that all our expertise doesn't lead to perfection. All our force isn't enough to take away the threat, so maybe we need to be humble and admit that we just try our best, and hope that our best will be enough to make a change....