The Islamic concept of Ummah is International Nationalism

http://en.wikipedia.org/wiki/Ummah

The concept of Ummah was created to eliminate endemic amoral tribalism.  (It is really just the Muslim version of Christendom.) 

One of the possible translations for this is "nation".  Of course if you were a Muslim, you would have no problem in thinking that Islam would be good for any nation.

If you considered yourself a Nationalist - in the sense of wishing to adhere to an ideology that promotes the long term National Interest (rather than that of narrow petty divisive amoral tribal ideological politics and short term tactical advantage against the other party) - then you would find yourself obliged to consider whether it is in the National Interest to disestablish the Church of England and establish something more fit for purpose. There is no reason why Islam should not be considered for the British Nation mutatis mutandis, establishing an Islam that is unique to Britain or even calling it Anglican Islam ...

http://thevoiceofreason-ann.blogspot.com/2010/11/melanchthons-dan-hannans-trilogy-of.html

Were this to happen across Western nations then varieties of Islam such as American, Franco, Germanic Islam might emerge.  Indeed, it is possible that our lives might improve in the light of Koranic wisdom.  I am quite certain almost anything would be better than living in a state of Demented Feminism (which promotes female promiscuity amongst other social ills) and Liberal Extremism (which systematically cultivates failure) as we do now. 

Just supposing all the countries in the world embraced Islam.  Would this necessarily mean that there would be no wars ever?  Of course not.  In the event of a war, the nation that best practices Islam would win over a nation that practises Islam less well.  

Islam is after all a religion of peace and war, which sounds a lot more useful than being just a religion of peace, IMHO. 

To have peace be prepared for war, or, as the Romans would have it, Si vis pacem, para bellum.