A world government has been long overdue. But it will soon become possible, and soon enough become inevitable. The first step might be to create a bicameral legislature in New York. In the lower house each member country has a voting weight in proportion to its population. In the upper house it is in proportion to its GDP. Each member country pays 1% of its GDP in tax. That makes the world government's budget. The President of the World is required to garner a majority in both chambers, limited to two five year terms. Eventually when at least half of humanity has biometric IDs and can vote from mobile phones, the President of the World can be directly elected. Local, state, federal, global -- these would be the four layers of government everywhere on earth, except where the country might be too small, or too homogenous for a federal setup.
The world government is not the UN. It is a new thing, just like the UN was not the League Of Nations. There will be a President Of The World. There will be a global parliament. There will be a World Court. There will be the three branches. All global institutions will be subsumed by the world government.
This century is not the American, or the Chinese, or the Indian, or the Asian, or the African century. This is the global century. All world will become one country. The basic needs of all human beings will be met. Primarily because the Age Of Abundance is right around the corner, much of it technology driven.
Multinational corporations are already global, finance has long been global, but there is not the robust political framework. That robust political framework will also be good for the MNCs, also for global finance.