South Korean President Park Geun-hye, along with Vice President Biden. (Yonhapnews/European Pressphoto Agency)

It was a stark and, to some observers, jarring image: Park Geun-hye, the democratically elected president of South Korea, standing shoulder to shoulder with the authoritarian leaders of China and Russia at a lavish military parade in Beijing last month.

Park’s appearance along with Vladi­mir Putin in the guest box of Chinese President Xi Jinping at an event skipped by top U.S. and Japanese officials raised eyebrows in Washington and Tokyo at a time of growing worries in Asia about China’s expanding role in the region and the world.

The Obama administration’s strategic rebalancing of U.S. foreign policy toward Asia is aimed at establishing new partnerships and drawing allies closer as a hedge against China’s growing influence. And though the White House has offered no public criticism of Park’s decision, her broader efforts to deepen ties between Seoul and Beijing is expected to be at issue when President Obama welcomes her for a summit meeting Friday.

“Park is looking for an opportunity to articulate her strategy with China,” said Sue Mi Terry, a former CIA analyst on East Asia affairs. “She is straddling the fence between Beijing and Washington.”

Administration officials insisted that the U.S.-South Korea alliance remains on solid footing and emphasized that Park’s trip to Beijing had ancillary benefits as she pushed Xi to take a more active approach in pressuring nuclear-armed North Korea over its belligerent behavior.

President of South Korea Park Geun-hye, left, participates in a full military honors parade at the Pentagon. (Jim Watson/AFP/Getty Images)

Park’s attendance at the military parade “was a sovereign decision,” Mark Lippert, the U.S. ambassador to South Korea, said this week. But, he added: “It’s clear to us she made good use of her visit to push forward her agenda on North Korea. That’s a good thing. We believe China could and should do more on the North Korea issue.”

Park quickly sought to reassure Washington, meeting for lunch with Vice President Biden on Thursday to discuss “common strategic interests,” according to the vice president’s office. Biden reaffirmed the “unwavering U.S. commitment to deter and defend against North Korean provocations.”

In a speech at a the Center for Strategic and International Studies, Park said South Korea’s alliance with the United States “continues to evolve into an ever stronger and dynamic relationship.” Though she did not mention her strategy with China in detail, she alluded to the “complex and multidimensional” challenges in a world in which “the line between geopolitics and geoeconomics has become blurred.”

Park’s visit to Washington — rescheduled from June when she postponed a trip due to an outbreak of a deadly respiratory illness in South Korea — caps a year of high-profile White House summits with Asian leaders, including Japanese Prime Minister Shinzo Abe and Xi, as the administration’s Asia strategy enters a crucial stretch.

In the coming months, the outcomes of democratic elections in Burma and the White House’s push for congressional ratification of a 12-nation Pacific Rim trade pact will help determine whether Obama’s efforts to expand U.S. leadership in Asia take root.

Obama will participate in regional economic and security summits next month in the Philippines and Malaysia. Deputy national security adviser Benjamin Rhodes leaves Washington on Friday for meetings in Laos, which assumes leadership next year of a Southeast Asia forum, and Burma, also known as Myanmar.

White House officials believe that Obama’s personal engagement has helped pay dividends and contributed to a slight thawing of relations among the three major East Asian powers. Xi, Abe and Park are expected to hold a long-delayed trilateral summit in Korea in the next few weeks, a potential breakthrough in a region fraught with mistrust and deep historical grievances.

In particular, the Obama administration has placed an emphasis on improving communication between Tokyo and Seoul, as the United States seeks to harness allies in a unified response to China’s assertive maritime behavior in the East and South China seas.

For Park, however, the everpresent threat to South Korea posed by the North has prompted her to pursue closer ties with Xi in hopes of leveraging Beijing’s influence over Pyongyang. The U.S.-led “six-party talks” aimed at finding a diplomatic solution to North Korea’s nuclear threat stalled in 2008 after Pyongyang fired a ballistic missile.

Though China remains North Korea’s only international patron, Xi has had a distant relationship with dictator Kim Jong Un. Park’s appearance at the military parade might have appeared discordant in Washington, but on the Korean peninsula the image was “all about how she’s standing next to President Xi, where the North Korean leader should be standing,” said Victor Cha, who served as director for East Asian affairs in the George W. Bush administration.

“But there is the other dynamic,” Cha added, “which is the idea that the Chinese probably don’t perceive it that way. They perceive it as pulling President Park closer to [Xi] and away from the traditional U.S.-Japan-South Korea trilateral alliance.”

U.S. officials said they are not threatened by Park’s strategy, noting that Obama has visited South Korea more than any other Asian nation during his presidency.

The United States and South Korea finalized a free-trade agreement in 2011, and Park said Thursday that Korea is interested in joining the Trans-Pacific Partnership trade accord between the United States and 11 Pacific Rim nations. Administration officials said Obama and Park would discuss cooperation on cybersecurity and space exploration, as well as economics.

“We do not see these issues in zero-sum terms,” said Daniel Kritenbrink, the senior director for East Asian affairs at the National Security Council. “We encourage all countries in the region to have constructive relations with China. We, too, are pursuing constructive relations with China, but those relations are very complex.”