In the Esquire article, “The Pentagon’s New Map,” Thomas Barnett defined the Core and the Gap this way:

So how do we distinguish between who is really making it in globalization’s Core and who remains trapped in the Gap? And how permanent is this dividing line?

Understanding that the line between the Core and Gap is constantly shifting, let me suggest that the direction of change is more critical than the degree. So, yes, Beijing is still ruled by a “Communist party” whose ideological formula is 30 percent Marxist-Leninist and 70 percent Sopranos, but China just signed on to the World Trade Organization, and over the long run, that is far more important in securing the country’s permanent Core status. Why? Because it forces China to harmonize its internal rule set with that of globalization—banking, tariffs, copyright protection, environmental standards. Of course, working to adjust your internal rule sets to globalization’s evolving rule set offers no guarantee of success. As Argentina and Brazil have recently found out, following the rules (in Argentina’s case, sort of following) does not mean you are panicproof, or bubbleproof, or even recessionproof. Trying to adapt to globalization does not mean bad things will never happen to you. Nor does it mean all your poor will immediately morph into stable middle class. It just means your standard of living gets better over time.

In sum, it is always possible to fall off this bandwagon called globalization. And when you do, bloodshed will follow. If you are lucky, so will American troops.

In the glossary to Blueprint for Action: A Future Worth Creating, Thomas Barnett defined “Functioning Core” as:

Functioning Core Those parts of the world that are actively integrating their national economies into a global economy and that adhere to globalization’s emerging security rule set. The Functioning Core at present consists of North America, Europe both “old” and “new,” Russia, Japan and South Korea, China (although the interior far less so), India (in a pockmarked sense), Australia and New Zealand, South Africa, and the ABCs of South America (Argentina, Brazil, and Chile). That is roughly four billion out of a global population of more than six billion. The Functioning Core can be subdivided into the Old Core, anchored by America, Europe, and Japan; and the New Core, whose leading pillars are China, India, Brazil, and Russia.

and “Non-Integrating Gap” as:

Non-Integrating Gap Regions of the world that are largely disconnected from the global economy and the rule sets that define its stability. Today, the Non-Integrating Gap is made up of the Caribbean Rim, Andean South America, virtually all of Africa, portions of the Balkans, the Caucasus, Central Asia, the Middle East, and most of Southeast Asia. These regions constitute globalization’s “ozone hole,” where connectivity remains thin or absent in far too many cases. Of course, each region contains some countries that are very Core-like in their attributes (just as there are Gap-like pockets throughout the Core defined primarily by poverty), but these are like mansions in an otherwise seedy neighborhood, and as such are trapped by these larger Gap-defining circumstances.

Contrast against:

My initial definition of the Core has been and always will be: these are not places where America should expect to war. You can counter, “But we should expect to go to war with everybody all the time! That’s the only prudent thing to do.” But I disagree. A strategy of defending against all possibilities is not a strategy, but a ceding of all initiatives to your enemies. Plus, successful grand strategy is about maximizing your friends and minimizing your enemies. It’s not about a fair fight, but a completely unfair routing of your opponents. You just need to be clear about who those are and who your friends are and who you can live with and work with from among the undecideds.

If “Core” / “Gap” is merely some self-selected conflict space, where we refuse to be maneuvered into conflict, then we can shrink it by merely avoiding conflict when it presents itself. By this definition India has no Gap except Kashmir, because the Indian government just ignores insurgencies elsewhere.

If the likelihood of military conflict is a function of economic connectedness, global rulesets, etc, then likelihood of being a theater of armed conflict is a good description of the Core/Gap divide.

Georgia and Ukraine are connecting. They are new democracies. They are both in the WTO. They have been talks with the European Union and NATO, and hopefully more will come of this in the future. Paying attention to the direction of connectivity, Georgia and Ukraine are on their way “up” to the core.

Russia is disconnecting. It is a new dictatorship. Russia is not even close to being in the WTO. It has suspended its cooperation with NATO. Paying attention to the degree on connectivity, Russia is on its way “down” to the gap.