Agenda discussed at Sunday’s meeting of senior officials from the presidential office, Cabinet and ruling Saenuri Party included whether to allow the U.S. to deploy an advanced missile defense system here despite objections from China.

Though the discussion was held behind closed doors, it was unusual for ruling party lawmakers to sit with administration officials in a bid to reach a conclusion on a sensitive security matter. This scene showed that the strategic ambiguity Park Geun-hye’s government had taken on contentious issues between the U.S. and China had worn so thin that even Korean politicians doubt its usefulness.

A group of Saenuri lawmakers last week publicly called on the Park administration to accept a U.S. plan to deploy a Terminal High Altitude Area Defense battery in South Korea.

In response to their move, a presidential spokesman said there was no request from the U.S. to deploy a THAAD battery here. Therefore, he insisted, no consultations and no decision had been made between Seoul and Washington on the matter.

A day after the remarks, however, the U.S. forces command here issued a press release saying surveys were conducted last year on five candidate sites for a possible THAAD deployment.

The U.S. apparently judges that deploying an advanced missile defense system here will be essential for defending its military units against North Korea’s enhanced nuclear and missile capabilities. It seems implausible for South Korea to continue with its strategic ambiguity on the U.S. move, which many experts here note would also help strengthen Seoul’s defense posture.

Seoul should have made a decision on the THAAD deployment earlier and strengthened efforts to ease Beijing’s concerns that the measure would pose a threat to its security. Its approach based on what is called strategic ambiguity is now viewed by critics as strategic confusion or strategic inactiveness.

It would have been a more strategic approach to try to convince China that the advanced missile defense system would be withdrawn from the South if nuclear and missile threats from the North were removed.

South Korea has also been pulled in opposite directions by the two superpowers over the issue of joining a China-led financial institution. It would serve Korea’s economic interests to be a founding member of the Asian Infrastructure Investment Bank, but Seoul has delayed its decision on the matter under pressure from Washington, which sees the new lending institution as rivaling the U.S.-led global financial system.

The U.K.’s decision last week to join the AIIB at the risk of straining ties with its most important ally suggests South Korea could have been bolder in dealing with the issue.

The THAAD deployment and the AIIB entry are seemingly unrelated to each other. But a more strategic approach based on cold calculations may give Seoul some leeway to enhance its national interests on the two issues.