I've never understood the opposition to a global government. It always seems to come from conspiracy theorists that lack critical thinking skills. What are we suppose to do? Never become united? Remain separate entities constantly vying and warring for territory and power? Does that really sound like the intelligent thing to do?
It's not about intelligence, it's a lack of an ability to root out qualities that are innate to human beings. Europe can't even unite itself for economic gain. They tried, and there are still all the individuals countries bickering over which group of deadbeats is sinking the Euro. Tribalism is inherent to humanity, and people you don't identify with will always be outsiders and a threat to your "tribe." You will never defeat this, and therefore will never unify under one government, because it would require people to sacrifice their tribal/national identities to some sense of a greater cause, and people are reluctant to do this on a small scale. Forget the global scale.