The Kingdom of Scotland attempts to build a colony in modern day Panama, goes bankrupt, looks to the English for support, leading to the creation of modern day Britain as well know it.
https://en.wikipedia.org/wiki/Darien_scheme
The Soviets being scared by Reagan's far out orbital SDI promises ("the Star Wars program"), causing them to overspend on defense and eventually go bust.
https://en.wikipedia.org/wiki/Strategic_Defense_Initiative
Not saying anything this drastic will necessarily happen to South Korea, but it's not the first time in history that a ridiculous boondoggle led to problems for an entire nation's finances.