International Space Agency?

How would the creation of an International Space Agency affect human affairs in space? I feel like, if we all just banded together, the cost of production for spacecraft would go down, the amount of ideas and scientific research could increase, and we, as a race, would actually be able to expand onto the Moon, Mars, and begin mining and colonizing asteroids. Either that or it would be like any other government and bicker over meaningless details and get nothing done. I would like to hear others opinions though.