The question is tempting and defies any straight forward answer. Experiences of various regions in the world are quite different. I would briefly take two examples:

1. The insurgency in North Eastern parts of India has over six decades of history. For all the failures that one may attribute to the Indian state in bringing peaceful settlement to each of the grouses by insurgent groups in the region, one single credit must also be given to it - it has successfully instilled a desire in all the groups operating in the region to enter the political arena as political entities, contest elections and appropriate power through democratic means. The reduction in armed violence and the number of indigenous political outfits that have entered and successfully secured power through electoral process in the past decade testifies to the first hypothesis.

2. Elsewhere, in Africa, countries like Botswana have started proper education programs for its citizens and officials on the workings of institutions of democracy (for example, the Election Department). By enhancing citizen and official awareness they have brought about a desire for responsible change - through democratic institutions - thereby reducing the scope for conflicts and violence. See www.ned.org for more inputs on this aspect.

Democracy does not automatically guarantee absence of violence. Inclusive democracy, where citizens find expression in government decision making, reduces the scope for conflicts. Transparency and accountability on the part of government machinery further contributes to people's faith that their genuine aspirations can be fulfilled through peaceful expressions. Controlling corruption in public life is another important aspect of governance that enhances ordinary citizen's faith in governance. It is by adopting to these that we can avoid the fructification of hypothesis 2.

Hope this helps. Have a great day!!

In principle, my answer is yes. Human history is very violent and if there exist opportunities, people are ready to exploit them. This supports hypothesis two. In order to elaborate further Srinivasan Rajamanickam’s examples: first, there are many other successful examples of peace mitigation that could therefore be used more often; second, there is no consensus on the definition of democracy (see Diamond, L. 2008. The Spirit of Democracy: The Struggle to Build Free Societies throughout the World. New York: Henry Holt and Co. p. 196.); third, the rate of democracy does not correlate well with national income per capita but ease of doing business rank and especially corruption perceptions index correlate much better (see my recent book, attached below, pages 149-161, 195). Botswana, for example, had the lowest corruption in Africa (for a short assessment of Botswana’s success see p. 288-289 in my book).

Book Missing a Decent Living for Everyone: Success and Failure in...

Not quite to the point, but if there is no "out" for the group which was previously more violent, then they will fear what "democracy" might serve them up and resist this reform all the more viciously. Not quite to the point either, but consider that Indonesia's military retained a very high share of seats after "democracy", and that after many other conflicts, the military has retained exclusive powers. I don't know how to write this into the analysis, but I don't think that the analysis can be complete without at least thinking through these sorts of issues.