Yesterday I wrote about Steven Pinker's account of the long peace we have enjoyed for the two generations without a major great power war, in his new book, The Better Angels of Our Nature: Why Violence Has Declined .
Pinker goes on to what he calls the "new peace" - the decline in the past one generation of civil wars, low-intensity conflicts (warlords, raiders, gangs), terrorism, and, most importantly, genocide.
What reduces all of these intrastate forms of violence are effective states. The effectiveness of states is increased by democracy, open markets, and involvement in international organizations, including peacekeeping.
Effective democratic states are the best at reducing all of these forms of violence. Effective autocratic states are somewhat effective in preventing these forms of violence - unless the state itself is the cause of the violence, as it usually is in genocide. The biggest danger arises from failed or ineffective states, which become power vacuums and safe harbors for civil war, warlords, and terrorists.
It may seem that terrorism has obviously risen in the last generation, which includes the 9/11 attack. That one attack was indeed the single biggest act of terrorism in generations. But the incidence of terrorist attacks has gone down since the '60s and '70s. Terrorism is very hard to do effectively, almost never achieves its objectives, and usually undermines whatever support it starts out with the more terrifying it is.
It is too soon to tell if the new peace will also be a long peace. But the new forms of conflict do not come close to producing the same quantity of violence that the great-power wars used to create.
Things are getting better. We may rejoice in that.