South Korea's government has yet to point a finger directly at North Korea the deadly sinking of a navy ship in March. Still, many South Koreans are convinced Pyongyang was involved. If a link is established, South Korea has few short-term options for its response.
For just about any other two countries in the world, the deliberate stalking and destruction of a navy ship by a submarine, resulting in the death of 46 crew members, would be grounds for open war.
That is what many people in South Korea believe happened in March, when a South Korean warship was split in half by an explosion as it patrolled a maritime border disputed by the North.
Dan Pinkston, Northeast Asia analyst for the International Crisis Group, says if investigators confirm a North Korean role in the sinking, the South would indeed have the right to use force.
"However, I think that would be a foolish response, the costs would far outweigh any benefits of such an action," said Pinkston.
North and South Korea remain technically at war along one of the most heavily armed land borders in the world. Although combined U.S. and South Korean forces are seen as far superior to the North's impoverished military, any force against the North could trigger the firing of thousands of rockets and artillery guns along the border, most of them aimed at Seoul.
Military experts say in such a scenario, hundreds of thousands could be killed in the South Korean capital in a matter of hours.
Economists say a serious change in the security picture could also rattle South Korea's international financial profile, jeopardizing the trade and investment its economy depends on. Other observers say a military response by the South would play into North Korean propaganda and rally support for the government.
Instead of striking the North, Pinkston recommends South Korea should step up its participation in regional security.
"They should signal clearly to North Korea that the Republic of Korea will fulfill all of its commitments as a full participating member of the Proliferation Security Initiative," added Pinkston.
More than 90 nations have joined that initiative, begun by the United States in 2003. It coordinates international intelligence and naval activity to disrupt the transportation of weapons of mass destruction. South Korea has restricted itself to "observer" status to avoid raising tensions with the North.
South Korean President Lee Myung-bak is scheduled to discuss a range of security steps with his top military leaders on Tuesday. Pinkston says the Cheonan incident is likely to fuel a strengthening of the South Korean military's ability to monitor and prevent such occurrences in the future.
"In the long run, the response from the Republic of Korea and the strengthening of its military forces will actually worsen North Korea's security," added Pinkston.
In the short run, however the South has indicated it will take a diplomatic approach, by bringing the Cheonan sinking to the United Nations Security Council.
The council has already sanctioned North Korea heavily for its two nuclear weapons tests, and few experts think there is room for new sanctions. However, Baek Seung-joo, with the Korea Institute for Defense Analyses in Seoul, says U.N. members such as China can be reminded to increase enforcement of existing sanctions.
He says China's failure to effectively enforce the sanctions gives North Korea the wrong signal that it can misbehave in the international community.
Baek recommends South Korea also get more active in helping the North Korean public get informed.
He says we have to do more to provide outside information directly to the North Korean public in a systematic way, using technologies like broadcasting.
Some North Korea scholars say even though authorities may find it distasteful in the short run, the South should continue to operate a joint industrial zone in Kaesong because it is in the long-run interest of unifying the two countries. They say South Korea and the United States should push forward with six-nation talks aimed at ending the North's nuclear weapons programs. Abandoning the talks, they say, would give the North another excuse to build more weapons.