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

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

The idea of installing a global governing body, instead of having separate establishments administering their own countries, has long been debated. While such a system might have some merits, I strongly believe that the drawbacks clearly outstrip the former. 

Advocates of this arrangement argue that having a unified regime for the whole world can help resolve numerous global issues, and help develop harmony and respect among diverse cultures.  Additionally, a majority of  international conflicts arise due to the hunger of capturing territorial rights of the others, but engendering this system would outrightly eradicate  cross-border disputes.  For instance, a major portion of the budgets of every country is allocated to strengthen defense systems, to safeguard their borders from potential threats from the neighbouring countries. 

In contrast, many believe that such a set-up can prove to be disastrous, rather than a positive development. This could lead to the government acting arbitrarily at their own whims and fancies, thereby neglecting the actual issues influencing localized circumstances, causing chaos rather than bringing clarity. Additionally, it would undermine the true essence of democracy and would prove to be regressive, by paving the way for authoritarian rules. For instance, in many countries, authoritarian regimes have failed to establish social harmony, rather they have instilled fear and have taken control,  whereas democratic settings extend absolute freedom in almost all walks of lives.  These two different ways of lives would prove to be compatible and thus result in conflicts of interest causing disorder.   

In conclusion, this proposal fails to emanate optimism, as the shortfalls are much more disastrous which cannot be overlooked. The concept of uniform global government does not sit well in a fragmented world, wherein some are placed as democracies, while others are autocratic: the root of all conflicts.