What is interesting is that the ship was split in half!
South Korea has now publicly announced that the Cheonan was likely hit by a torpedo: see this NY Times article.
As Rob has noted, “War is simply not in South Korea’s interests.” So, I’d like to see some public opinion polling to see if the government will be pressured to take a more bellicose stance. War of Jenkins’ Ear anyone (a case in which, according to some, public opinion pushed the government further than it may have wanted to go)? I doubt it.
Update: Will the new rallying cry for the South Korean Navy be: “Remember the Cheonan”?