• South Korea's president stresses US alliance amid Trump's exercise cut.
• Trump's order to reduce joint military exercises with South Korea sparks concern.
• South Korea relies on US for national security and nuclear protection.
• US has about 28,500 troops in South Korea.

This development may indicate a weakening of the US-South Korea alliance, which could have significant implications for regional security. The move suggests that Trump's administration may be prioritizing relations with North Korea over its alliance with South Korea, which could lead to a shift in the balance of power in the region.