"as long as there is man.. there shall be wars" - Albert Einstien.
It is a simple fact. Human beings are neither ignorant, nor bigoted (unless they go out of their way to be so). We are biologically programmed to dislike that which is different, and exterminate that which is seemingly inferior.
The majority will always step on the minority. Not to turn this into a political, racial or something of the like thread, but to use an example.
In ten years time, Australia could become an Asian nation, with European Anglo Saxons as the minority. This will cause a major shift in the order of things, I can guarantee it. China's influence is growing stronger by the minute here, and is certainly showing no sign of stopping. In as many as 20 years, Australias number one religion (going by current information) would be Islam or Hinduism.
This is a complete role reversal, the minority becomes the majority. And therefore the dominant power on Earth. America is slowly but surely giving way to China. And even more conflict will result. Inevitably, I can see WW3 is not far off with resources dwindling and political tensions high around the world.
These may seem to be unconnected and irrelevant points. But what I am stating here, is quite obvious. The world is undergoing a MAJOR upheaval, religious fervor, political unrest, resource depletion. And the very basic emotional response of Racism. Is rife around the world, and in such an unstable environment, the only stability would be enforced INstability, e.g. Warfare.
One day the human race will be united, and I agree with Badkarma. The only thing to unite such a violent intelligent species such as ourselves, would be a common enemy to exterminate together. Otherwise, difference will get in the way of all, and conflict will invariably follow.
Afterthought: An example of the common enemy would be the 2nd World War. The only time you could get every nation on Earth "broad statement I know" to work together, was to defeat an enemy that would destroy all nations on Earth save their own.