I like a field of economics called "behavioral economics." Of course, behavioral economics isn't the correct answer to every problem, but it's an interesting way to look at things.

Anyhow, behavioral economics is based on the idea that people like to slack off. Many companies deal with this by firing the employees; and employees deal with that by doing just enough to not get fired (behavioral economics studies other ways to encourage employees to do things).

I've watched North Korea believing (1) China will do just enough to prevent the US from throwing its hands up in the air and giving nuclear weapons to Japan, India, South Korea and any other US allies in the region, and (2) North Korea will do just enough to keep Kim Jong-Il from disappearing one night through a Chinese special forces operation. It looks like the second scenario may play out.