Back home in the United States, American soldiers train hard to stay sharp. In a potential powder keg like South Korea, they train as if their lives depend on it. Someday in the future it just might.
"I feel like personally, I'm confident enough that I've been trained well enough to where if anything, heaven forbid, should arise, I'd be ready," Vallejo native Pfc. Shea Leano said.
Ready, the soldiers say, even if the North now has nuclear weapons.
"We're constantly, you know, on alert, we're always constantly looking out for things like that, anytime we hear about any kind of test, the alerts go up and we're ready in case something does happen," San Jose native Lt. Mayra Lopez-Nanez said.
There are about 4,500 U.S. soldiers based at the Yong San Army garrison, along with the two top U.S. Army generals in the country -- the commander of 8th U.S. Army and the commander of U.S. forces in Korea.
They occupy a garrison built by the Japanese army before World War II. It sits on prime real estate in the middle of Seoul, one of the world's largest cities.
Over the years, the South Korean people have developed a kind of love-hate relationship with the U.S. presence in their country.
In 2002, South Koreans protested by the thousands against the U.S. military after two young girls were killed in accidents involving American military vehicles.
But, seven years later, the anger has softened.
"We're technically in the middle of a war and you never know when the war is going to break out again, if the U.S. Army is not here, I think would feel insecure," computer programmer Nam Gyu Han said.
"If the U.S. Army wasn't in Korea, it is my assumption that South Korea would have gotten a certain level of threat from Kim Jung Il," student Bo Ryung Hwang said.
South Koreans may feel safer having American troops and technology in their country, but, the same has not always been true from the soldier's point of view.
Historically, Korea has been seen as a hardship post, with soldiers serving just a year before moving on, unlike Europe, where tours average two to three years.
The brevity of the tour, along with a lack of housing and other logistical headaches meant it was almost impossible for soldiers to bring spouses and kids along.
"Well under 10 percent of the troops here have their families with them, and it is a problem, it causes continual turbulence," 8th U.S. Army Commander and Portola Valley native /*Lt. Gen. Joseph Fil Jr.*/ said.
"I was here in Korea from 2001 to 2004 prior to this tour and when I first came here in 2001 there was still a large number of soldiers living in old Quonset huts that were put up right after the Korean War when the U.S. first established its bases here," Antioch native Maj. Lucas Hightower said.
But that is about to change. The top U.S. general in Korea has a plan for making the tour longer and more tolerable.
Thursday, ABC7 will find out how that will affect the defense of South Korea in an exclusive talk with Gen. Walter Sharp, commander of all U.S. forces in Korea.