North Korea is now threatening to close the land border with the South, essentially shutting down the Kaesong Industrial Complex:

North Korea’s military threatened Wednesday to shut its border with the South from next month.

It said the measure was caused by Seoul’s “confrontation activities” despite repeated warnings, but propaganda leaflets sent by civic groups here are considered to be the real reason behind the threat.

South Korea’s Ministry of Unification expressed regret over the announcement, urging the Stalinist state to respond to its calls for dialogue.

The threat came as South Korean civic groups have kept sending hot air balloons with more than 100,000 fliers attached to them containing criticism of the North’s dictatorship.

Nothing new, of course. When engagement projects are first proposed, they’re justified — honestly, I’d like to think — with arguments that they will give the outside world leverage over the North. Yet ultimately, they always seem to give the North leverage over its negotiating partners/shakedown victims.

Witness this brazen act of cravenness — CEOs of Korean companies at Kaesong asking the Unification Ministry to lean on civic groups sending leaflets into the North.:

CEOs of South Korean businesses at the inter-Korean industrial complex in the North Korean city of Gaeseong plan to meet with Unification Minister Kim Ha-joong today to discuss operations at the industrial site.

They will ask the ministry to persuade civic organizations to stop dropping leaflets on North Korea, a company executive said.

Good luck with that. I will confess, however, that the activities of the groups sending the leaflets into the North concern me. You have to wonder when an incident like the 1996 shootdown by the Cuban Air Force of a plane flown by Cuban-American activists engaging in similar activities will take place. Sinking a Korean fishing boat full of activists in international waters wouldn’t be entirely out of character for the North, and would be a perfect way to ratchet up tensions with the Lee Myung-bak administration.