RENEE MONTAGNE, HOST:
South Korea today took a step sure to irritate its communist neighbor. In response to North Korea's nuclear test, South Korea says it will resume blasting loudspeaker propaganda across the border. South Korea stopped doing that last summer after the two countries fired artillery shells at each other across that border. As for the nuclear test, there's still a lot of uncertainty about exactly what took place at North Korea's nuclear test site yesterday. On the phone with us now is Victor Cha. He is a senior advisor at the Center for Strategic and International Studies. Good morning.
VICTOR CHA: Good morning.
MONTAGNE: It's of course now the day after North Korea claimed to have detonated a hydrogen bomb. What can we say about what actually happened?
CHA: Well, Renee, we still don't know for sure. People are basing their assessments on the seismic readings which seem to suggest it was not a hydrogen bomb. It's not - the readings are not large enough for it to be a hydrogen bomb. Nevertheless, this is the fourth nuclear test by North Korea. It was more powerful than the three previous tests, and they're clearly advancing their program with each test that they do.
MONTAGNE: Well, whatever was tested - and clearly, as you say, something was tested - it would seem to send a message to the people of the world that would be the message of Kim Jong Un. What would that be?
CHA: Well, I think probably the main message is that they are - both domestically and internationally, they're trying to show with this test that this leader who has just come to power about four years ago is fully in control. They have a major gathering of the Communist Party in the spring, only the seventh one in the history of the country, in which I think they're going to try to celebrate the coronation of this young fellow as the leader. And so this is both a sign of strength outwardly, as well as domestically, to show that this is the man who's in control.
MONTAGNE: Well, of course North Korea has approximately one important ally, and that's China. And yet, even China has criticized it about this test. What influence does China have over North Korea?
CHA: Well, on paper China has a great deal of influence because they're really the only country today that does a large amount of trade and assistance with North Korea. But the Chinese say publicly that they don't have a lot of influence because they're largely unwilling to use that assistance as leverage to get the regime to do what we want it to do. The reason they don't want to do that is they're afraid that they're going to collapse the regime or destabilize it. And for China, a destabilized North Korea on their border is as scary as a nuclear North Korea that's doing nuclear tests, if not more scary.
MONTAGNE: Well, just briefly - we just have a few seconds, but what impact have sanctions had on North Korea?
CHA: The - North Korea's been under sanctions for a long time. Clearly, they have not had an impact on North Korea's nuclear program, the development of the program. But there's still more sanctioning that can be done. If you compare North Korea to Iran, the level of sanctioning in North Korea is a fraction of what was done to Iran. So I think there's still some space there that the U.N. and that the United States and its allies will look at going forward.
MONTAGNE: Well, thank you very much for joining us.
CHA: Thank you.
MONTAGNE: Victor Cha was director of Asian affairs at the National Security Council under President George W. Bush.