Democracies have a tough time with conscription, because it affects so many voters and the voters can just decide to get rid of it. That's what happened in Britain in the 1950s, the U.S. in the 1970s and most other democracies since. But not South Korea. Faced with over a million hostile North Korean troops, South Korea has had to rely on conscription to fill the ranks of its 650,000 man active forces. But there's a problem, in that currently only 160,000 of those troops are conscripts, and 345,000 young men become eligible for military service each year. In other words, the armed forces only need about a quarter of the 18 year olds that become available each year. Actually, men are usually drafted at the age of 19 or 20, and a generous list of exemptions (like being an orphan, or having too many tattoos) let about 40 percent walk free (of any military obligation.) The vast majority of the conscripts go into the army, where they serve 26 months, followed by six or more years in the reserves. For over a decade, the air force has gotten by with just volunteers, and the navy nearly so.
Over the years, the wealthier and better educated kids were more likely to avoid service. It became common to think of conscription as something only the children of the poor and uneducated were subject to. But this attitude was not politically popular. In 1999, a law was passed making it mandatory for politicians to reveal if their sons had served in the military. A recent scandal arose out of the custom of wealthy and middle class families sending their sons out of the country to avoid conscription. But sometimes the kids were just gone on paper, and were still in South Korea. A minor industry has grown up around scams to avoid doing military service.
South Korea is having a problem with draft dodgers. The government recently admitted there are currently 9,000 South Korean young men dodging military service by falsely claiming they are out of the country. Thousands more have used other scams to avoid military service.
Replacing the conscripts would be expensive, for the pay would be much higher than the less than twenty dollars a month the conscript troops now get. But it's not really about money, for the South Koreans could afford an all-volunteer force. What they can't afford is a sense that the wealthier and better educated families are avoiding service while poor kids serve instead.