The world should have only one government rather than a national government for each country Do the advantages out outweigh the disadvantages

There are some thoughts that the world should have one government only rather than separate governments in every country. This idea, though it comes with certain advantages, would potentially create problems which are insoluble.
To some proponents, the conflicts between regions, can be easily solved by the global mono – governments. For example, the US federal government has been addressing problems among the states ever since their establishment. However, the key to their success is due to the fact that they only work well in a small range of over 50 states, and most citizens believe in rights like individualism and capitalism. Otherwise, a single governments would hold thousands of states or regions, making it impossible to manage and it would actually not necessitate compromises.
But some theorists have postulated a more advanced idea. Such as, taxes could be equally collected and redistribute to areas that need them, then there would be no more inequality and poverty, but in fact, tax payers in richer areas would received very little money in return thought they payed more, which would eventually trigger resentment, unrelenting demonstrations and social unrest.
Another thing is, the idea of no boundaries with immigrants may sound convincing, people can travel from countries to countries without any strict verification procedures. Migrants would come to more developed places to find better jobs, making those places economic concentrated areas. But stiffer competition for housing, jobs and traffic would soon happen, and the worst thing that could occur is those areas would be a breeding ground for any kinds of crimes.
In summary, even though there is some potential in having one government for the whole world, we can see a lot more drawbacks rather than the actual benefit.