The sight of President Park Geun-hye standing alongside Chinese leader Xi Jinping, with Russian President Vladimir Putin placed between them, at a massive military parade in Beijing on Thursday may well be seen as signaling what some observers call a seismic change of the diplomatic configuration in Northeast Asia. Choe Ryong-hae, a key aide to North Korean ruler Kim Jong-un, was seen at the end of a row of foreign dignitaries watching the parade from a rostrum overlooking Tiananmen Square.

It was a snapshot of deepening ties between South Korea and China, which were battlefield foes during the 1950-53 Korean War in which China fought alongside North Korea, and estranged relations between Beijing and Pyongyang.

Western leaders skipped the military parade, widely seen as a show of force by an increasingly assertive China.

Park’s attendance at the event has drawn some concern from Western capitals that South Korea may be tilting toward China. It underscores, however, Seoul’s crucial interests in consolidating cooperation with Beijing in persuading Pyongyang to give up its nuclear weapons programs and, more ultimately, achieving reunification of the peninsula.

During her summit with Xi on Wednesday, Park expressed gratitude for the constructive role China had played in defusing recent tensions on the peninsula.

Park’s high-profile attendance at the military parade certainly helped consolidate strategic partnership between Seoul and Beijing and win Chinese hearts. But it has also left South Korea with equally important tasks of strengthening alliance with the U.S. and improving strained ties with Japan.

During her summit talks with U.S. President Barack Obama in Washington next month, Park should make her best pitch to ease U.S. concerns about Seoul getting closer to Beijing. As some experts here note, it may need more efforts beyond her upcoming U.S. trip to ensure the Seoul-Washington alliance will not be affected by enhanced partnership between South Korea and China.

Park’s agreement with Xi to push for holding trilateral summit talks with Japanese leader Shinzo Abe later this year has opened the way for improving Seoul’s frayed ties with Tokyo. If the three-way meeting is held in Seoul as envisioned, first bilateral talks may be set up between Park and Abe. This will be in tune with Washington’s hope to see better relations between its two key Asian allies.

If it proves instrumental in deterring Pyongyang’s further provocations, including a possible long-range missile launch, the strengthened partnership between Seoul and Beijing may help South Korea take an initiative in promoting trilateral cooperation with the U.S. and Japan.

South Korea should also play an effective role in bridging differences between China and the U.S. over the resumption of six-party talks on dismantling the North’s nuclear arsenal.

Seoul officials now need to exercise strategic wisdom and adroitness to ensure Park’s attendance at the sensitive event in Beijing will result in triggering a virtuous cycle of forging better security conditions in the region.

Presiding over the military parade, Xi said that no matter how much stronger it might become, China would never seek hegemony or expansion and never inflict its past suffering on any other nation. Constructive partnership between Seoul and Beijing, which contributes to regional peace and stability, will help ease the world’s dubious eye on China’s true intention.