From reports of Korean comrades, there have been as many as 100,000 people at these demonstrations which often go on all night. There will be a 72 hour protest starting June 5, building up for the next big demo which is planned for the memorial day for the death of Lee Han Yul on June10 -- a tear gas cannister struck him in the head at a student protest at Yonsei University in support of the 1987 Great Strike (3479 strikes occurred that year, most of them between June and September) and he later died in the hospital -- and they expect a 1,000,000 people to come out for the anti-beef protest. Yonsei will be closed this year to combine the 2 events. The KCTU union is planning to do a general work stoppage in support of the demos on that day as well.
But sometimes it's the tail wagging the dog. The government pretends to oppose the protesters, but it often stirs up these nationalist demonstrations when it needs them to maintain protectionist measures that more powerful capitalist institutions (IMF, WTO, OECD, trading partners like the U.S., etc.) demand they eliminate. One example I witnessed when I lived in Seoul was in the late 1990s and school children, stirred on by the school principle and teachers, burned empty Japanese and American cigarette boxes and empty imported Scotch and Cognac boxes in effigy to protest against the import of "luxury" goods, which they alleged were undermining the Korean brands -- and in the case of cigarettes it undermined the government-run monopoly on tobacco (the latter part of the nationalized conglomerate that's also a ginseng monopoly).
Correction to the above:
I have been corrected by a Korean comrade who states that the new Lee Myung Pak government is in crisis because of their ready acceptance of the Free Trade Agreement allowing U.S. beef subjects Koreans to the risk of Mad Cow Disease. The popular sentiment is that the Lee government is so little concerned with health risks and is more concerned with toadying to the needs of global capital.


In the kind of situation Upton Sinclair fell into; aim for the heart, hit people in the stomach.