Atheist nations are more peaceful: there are several possible reasons for this. It could be that people living in turbulent countries turn to religion, or it could be that religion is not a good way to structure modern society. Or it could be that some other factor or combination of factors (democracy? free speech? education? government welfare?) generates citizens who are both peaceful and non-religious.
Peace index ranks New Zealand the safest country in the world: Britain up slightly to 35th position, US up six places to 83rd while Iraq sits at the bottom of the list
Global Peace Index 2009 (Countries most at peace are ranked first.)
New Zealand
Denmark
Norway
Iceland
Austria
Sweden
Japan
Canada
Finland
Slovenia
Czech Republic
Ireland
Luxembourg
14º
Portugal (2008: 7º, 2007: 9º)
Global Peace Index 2009 (Countries most at peace are ranked first.)