U.S. President Joe Biden delivers remarks at the U.S. Conference of Mayors in Washington D.C., U.S., Jan. 17. Reuters-Yonhap

Outgoing U.S. President Joe Biden is set to leave office next week, handing over to his successor Donald Trump a reinvigorated network of America's alliances and partnerships, and a disheartening scorecard on efforts toward the denuclearization of the Korean Peninsula.

Biden's presidency is set to end at noon Monday, when Trump will be officially sworn in as the United States' 47th president to face a full plate of nettlesome policy challenges, including North Korea's evolving nuclear threats and its growing military alignment with Russia.

Four years ago, Biden came into office on a pledge to knit back America's alliances that he claimed had "atrophied" during Trump's first term, as the Democratic president repeatedly stressed the importance of allies and partners as the U.S.' "greatest strategic assets."

Over the past years, the Biden administration has indeed delivered on the pledge to strengthen the U.S. alliance-based cooperation network to confront shared challenges, ranging from maritime security to technological advances to supply chain resiliency.

It has pursued a "lattice-like" architecture, which involves bringing together America's regional allies for multilateral cooperation to respond to China's increasing assertiveness and other challenges, in a move away from a "hub-and-spoke" system that centers on bilateral alliance cooperation.

Progress in Biden's pursuit of a robust alliance system was most salient in the forging of the trilateral partnership among South Korea, the U.S. and Japan — a task that gained traction due in part to now-impeached President Yoon Suk Yeol's decision to address the issue of Japan's wartime forced labor in March 2023.

"We did it — what few felt was possible to build the first-ever trilateral partnership between the U.S., Japan and South Korea ... drawing close to our Pacific allies to defend our shared security and prosperity," Biden said in a speech at the State Department last week.

The three countries' cooperation culminated in the first-ever standalone trilateral summit among Yoon, Biden and then Japanese Prime Minister Fumio Kishida at Camp David in Maryland in August 2023. It produced a series of landmark agreements, including the "Commitment to Consult" each other in the event of a shared threat.

Since the summit, the three sides have launched a system for the real-time sharing of North Korean ballistic missile warning data, created a trilateral military exercise named "Freedom Edge" and installed a trilateral secretariat to institutionalize their cooperation.

Moreover, the Biden administration has further reinforced the Quad security forum that consists of the U.S., Australia, India and Japan, and led the creation of the AUKUS security partnership involving the U.S., Britain and Australia.

It has also pushed for stronger cooperation between the North Atlantic Treaty Organization and the transatlantic alliance's four Indo-Pacific partners — South Korea, Japan, Australia and New Zealand.

Despite substantial progress in the reinforcement of these fit-for-purpose groupings, there has been little headway on efforts toward the oft-repeated goal of the "complete" denuclearization of the Korean Peninsula.

President Joe Biden, left, and Vice President Kamala Harris watch during a Department of Defense Commander in Chief farewell ceremony at Joint Base Myer-Henderson Hall in Va., U.S., Jan. 16. AP-Yonhap

"We, like our predecessors, going back to Clinton, we're obviously not able to make substantial progress on the issue of denuclearization of the Korean peninsula. The trend there continues in the wrong direction, as it has under multiple presidents," Jake Sullivan, Biden's top national security adviser, told reporters this month.

"I didn't come in with particularly optimistic views on what we would be able to accomplish, but that's an area that remains of considerable concern," he added.

Although Washington repeatedly expressed its desire to engage with Pyongyang "without preconditions," its overtures fell on deaf ears. Pyongyang has defiantly doubled down on its nuclear and missile programs as evidenced by its relentless weapons tests, including its recent test of a hypersonic ballistic missile.

The threat from the North further escalated as the recalcitrant regime has been striving to deepen its military cooperation with Russia in line with the "Comprehensive Strategic Partnership" treaty that North Korean leader Kim Jong-un and Russian President Vladimir Putin signed last year.

To deter the threats, the Biden administration sharpened its focus on bolstering nuclear deterrence for South Korea — and deterring the Asian ally from considering its own nuclear program.

A key achievement of nuclear deterrence cooperation between Seoul and Washington was the launch of the Nuclear Consultative Group (NCG), the allies' key deterrence body introduced in the Washington Declaration that Yoon and Biden signed during their summit in April 2023.

Under the NCG framework, Seoul and Washington crafted nuclear deterrence guidelines in July in a milestone to enhance the credibility of America's extended deterrence commitment to using the full range of its military capabilities, including nuclear, to defend its ally.

It remains to be seen whether the incoming Trump administration will inherit the alliance-based cooperation mechanisms created under Trump. But observers say that Trump might see the value of the cooperative bodies as the U.S. cannot act alone to address regional and global challenges.

"This notion that allies are liabilities or free riders is simply not true," Vipin Narang, former acting assistant secretary of defense for space policy under Biden, told a forum this month, calling the allies "force multipliers."

"When we provide a united front to our adversaries, we are stronger, and the allies provide capability and geography, and we share values," he added. (Yonhap)