As we all know, there are many crucial international issues human civilization as a whole have not yet properly dealt with. The only way to properly establish a Utopian society we can all be proud of is to bring the human race under one unified federation, ran under a strong central government, therefore we can deal with crucial international issues more quickly and efficiently, such as extreme poverty and war in certain parts of the Sub-African continent.
Not only this, however in the near future, when permanent colonization of Mars and other planets becomes a reality, there will still be land feuds and potentially large wars started from them.
This is a lengthy and difficult process to take in, however it will help human civilization establish a better tomorrow for future generations