President Yoon Suk Yeol’s rescinded martial law declaration will test relations with the U.S., and raises questions about the nearly 30,000 American troops in the country.

During South Korea's decades under autocratic governments and military rule, martial law was a common response to political instability.

South Korea is reeling over a shock martial law declaration by President Yoon Suk Yeol, whose short-lived gamble will have major implications.