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Editor’s Note: Frank Aum is senior expert for North Korea at the United States Institute of Peace. He was the senior adviser for North Korea in the office of the Secretary of Defense from 2012 to 2017. S. Nathan Park is a Washington-based attorney whose commentary on the Korean Peninsula has appeared in the Wall Street Journal, Washington Post, Financial Times, Atlantic and Foreign Policy. The views expressed in this commentary are solely their own. View more opinion articles on CNN.

(CNN) —  

Two weeks ago in Pyongyang, North Korean leader Kim Jong Un and South Korean President Moon Jae-in signed a historic joint declaration in support of peace on the Korean Peninsula. But North Korea also vowed that it would only take major denuclearization steps if the United States takes “corresponding measures,” including declaring an end to the Korean War, which President Donald Trump reportedly told Kim he would do during their June meeting in Singapore.

Frank Aum
Frank Aum
Frank Aum

S. Nathan Park
Danielle Cho
S. Nathan Park

Trump continues to be complimentary toward the North Korean leader – going so far as to say at a recent rally that they “fell in love.” And, in his speech before the United Nations, Trump thanked Kim “for his courage and for the steps he has taken.” But administration officials and many Korea experts remain skeptical about the wisdom of declaring an end to the Korean War – which is technically ongoing since the 1953 Armistice Agreement only formalized a ceasefire – because they fear it could pave the way to undermining the US security posture in the region.

However, these concerns shouldn’t paralyze the Trump administration’s ability to seize the best opportunity for peace and denuclearization on the Korean Peninsula in decades. We should not let bureaucratic inertia and the fear of a potential disruption to our status quo defense posture in the region constrain our ability to achieve even greater security by building a new peace paradigm on the Korean Peninsula.

An end of war declaration would provide a low-cost way of testing the hypothesis that Kim will denuclearize if he can be assured of a better relationship with the United States. Kim already possesses nuclear weapons, and he may never give them up. But in Singapore, he at least committed to going down the denuclearization path, as he shifts his focus to improving his country’s economy and welfare. An end of war declaration would encourage Kim to stay on this path.

If, after an end of war declaration, North Korea doesn’t take further denuclearization measures, we will know that Kim is not serious about denuclearization under any circumstance. We can correctly characterize Kim as no different than his father and grandfather in his unwillingness to denuclearize. The United States can tell China we tried its preferred approach of negotiating with North Korea to no effect. The United States can then move forward with a policy that recognizes the reality of a nuclear North Korea that needs to be contained and deterred.

All diplomatic negotiations involve a give and take. North Korea certainly didn’t agree to denuclearize unilaterally while receiving nothing in return. But in agreeing to an end of war declaration, the United States would not be giving up much: It would merely recognize the reality that, as a practical matter, the war has been over for decades. However, the declaration is potentially a game changer for the Kim regime, which fears for its survival and foreign encroachments on its sovereignty. The formal expression of the end of the “hostile” US policy, as Pyongyang sees it, may help Kim neutralize the hardliners within his regime, creating greater flexibility to take further steps toward denuclearization. As a nonbinding political measure, a declaration would not require lengthy, complicated negotiations like a peace treaty. Most importantly, it gives forward momentum to the negotiations, allowing the bicycle to stay upright, as diplomats like to say.

Critics of the end-of-war declaration argue that it may weaken the United States-South Korea alliance. Declaring the war over, the argument goes, would give Pyongyang, Beijing and Trump the rationale to demand removal of the 28,500 US troops stationed there. Eventually, after several years of relative peace, South Korea may question the alliance altogether, seeing it as an impediment to Korean reunification.

These concerns are warranted and not inconsequential. For over six decades, the alliance, including US troops in the country, has deterred North Korean aggression, enhanced America’s ability to project power and influence and contributed to peace and prosperity in East Asia.

To mitigate apprehension about an end of war declaration, all sides should agree that there will be no changes to US forces and the Armistice Agreement until a more comprehensive peace agreement can be negotiated. Both Moon and Kim have reaffirmed that an end of war declaration would not affect the US troop presence on the Korean Peninsula at any rate.

Yet the concerns about the end of war declaration undermining the US-South Korea alliance also underestimate the resilience of the alliance, and the US ability to recalibrate our strategic posture. The 1953 Mutual Defense Treaty remains the cornerstone of our security relationship with South Korea, but since then, our bilateral partnership has widened into a more comprehensive alliance that goes beyond the North Korean threat, and encompasses political, economic, social and cultural cooperation.

The size of our military presence on the Peninsula is not a barometer of the US defense posture or the alliance’s health. The number of US troops has constantly evolved – from 70,000 in the 1950s to 38,000 in the 2000s to 28,500 today – adapting according to the strategic, military and political demands of the times. Nor is it the case that the US troops are present in South Korea only because of North Korea. In his recent interview on Fox News, Moon made this point clear: “The US forces in [South] Korea is not only beneficial for our deterrence vis-à-vis North Korea, but also it plays a larger role in terms of upholding peace and stability in the North East Asian region as a whole.”

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Furthermore, South Korea remains a steadfast ally. Public support for the alliance has hovered in the 90% range for the last eight years, bolstered by lingering concerns about China and Japan. Even Moon, who has been criticized for undermining unity with Washington by pushing aggressively for inter-Korean cooperation, has constantly stressed the need to develop the alliance into an “even greater” one. Indeed, in his Fox News interview, Moon would envision the US forces in Korea remaining in place “even after the unification [of the two Koreas] is achieved.”

Only a year ago, the Korean Peninsula faced “fire and fury.” Since then, a commitment to diplomacy by all the countries involved has created a chance for lasting peace. The end of war declaration would be another step in the right direction. The US-South Korea alliance often describes itself as standing “shoulder-to-shoulder” with “no daylight” in between. The two allied leaders should have the courage to trust the strength of the alliance and boldly pursue peace.