Photo Illustration: Getty Images/Shutterstock/CNN
Now playing
02:02
Why Singapore was chosen for Trump-Kim summit
Korean Central TV
Now playing
01:09
Watch Trump salute North Korean general
KCTV
Now playing
02:37
Kim Jong Un receives hero's welcome
ABC News
Now playing
01:01
Trump touts trust with Kim in TV interview
Now playing
00:53
Trump: N. Koreans in prison camps are 'winners'
North Korea leader Kim Jong Un (L) and US President Donald Trump shake hands after their meetings at the Capella resort on Sentosa Island in Singapore on June 12, 2018.
SUSAN WALSH/AFP/Getty Images
North Korea leader Kim Jong Un (L) and US President Donald Trump shake hands after their meetings at the Capella resort on Sentosa Island in Singapore on June 12, 2018.
Now playing
01:58
How significant was the Singapore Summit?
Kevin Lim/THE STRAITS TIMES
Now playing
02:11
Memorable moments from the Singapore summit
CNN Illustration/Getty Images
Now playing
02:58
Singapore summit: How did we get here?
CNN
Now playing
02:07
Trump talks denuclearization, sanctions and Kim Jong Un
Photo Illustration/CNN/Getty Images
Now playing
03:23
Trump and Kim Jong Un's ups and downs
Now playing
01:46
Trump shows Kim Jong Un presidential limousine
North Korea leader Kim Jong Un and U.S. President Donald Trump exchanged signed documents at the Capella resort on Sentosa Island Tuesday, June 12, 2018 in Singapore.
Evan Vucci/AP
North Korea leader Kim Jong Un and U.S. President Donald Trump exchanged signed documents at the Capella resort on Sentosa Island Tuesday, June 12, 2018 in Singapore.
Now playing
01:36
What Trump learned about Kim Jong Un
Now playing
02:34
Trump, Kim Jong Un sign 'historic document'
Pool
Now playing
01:24
Watch Trump, Kim Jong Un speak before summit
Pool
Now playing
00:32
President Trump, Kim Jong Un meet in Singapore
POOL
Now playing
02:23
Trump to Kim: We will be successful
North Korea's leader Kim Jong Un (L) shakes hands with US President Donald Trump (R) after taking part in a signing ceremony at the end of their historic US-North Korea summit, at the Capella Hotel on Sentosa island in Singapore on June 12, 2018.
ANTHONY WALLACE/AFP/Getty Images
North Korea's leader Kim Jong Un (L) shakes hands with US President Donald Trump (R) after taking part in a signing ceremony at the end of their historic US-North Korea summit, at the Capella Hotel on Sentosa island in Singapore on June 12, 2018.
Now playing
01:58
Amanpour: Trump can be a bully or a pussycat
CNN
Now playing
02:09
Rodman gets emotional discussing North Korea
(CNN) —  

If Donald Trump and Kim Jong Un make peace and agree to denuclearize the Korean Peninsula in their Singapore summit, the benefits would be felt across the region, not least in China, or so conventional wisdom has it.

Beijing would presumably see the threat of war in a bordering country almost disappear, trade sanctions lifted and a longtime ally in Pyongyang enter a new era of stability.

Not so fast, Asia analysts say. Beware the law of unintended consequences.

“Stability on the (Korean) Peninsula might mean the US is freer to pursue strategic competition with China than it is now,” said Corey Wallace, an Asian security analyst at Freie University in Berlin.

That competition has come to the forefront in the run-up to the June 12 summit as US-China tensions have spiked over Chinese military fortifications on man-made islands in the South China Sea.

“Despite China’s claims to the contrary, the placement of these weapon systems is tied directly to military use for the purposes of intimidation and coercion,” US Defense Secretary James Mattis told the Shangri-La defense forum in Singapore last weekend.

That’s a challenge the US is prepared to stand up to both now and into the future, Mattis said.

“Make no mistake: America is in the Indo-Pacific to stay. This is our priority theater,” said the defense secretary.

Wallace and other analysts said an easing of tensions in Korea could free up some of the tens of thousands of US forces deployed on the peninsula.

“Those troops are currently committed to Korean contingencies and in most China-related conflicts it would be very difficult for the US to employ forces based on the peninsula,” said Timothy Heath, senior defense analyst at the RAND Corp. think tank.

01:27 - Source: Department of Defense
US admiral: China is our biggest challenge

With responsibility for protecting South Korea reduced, those forces could be used to project US power in other parts of the Asia-Pacific such as Japan, Singapore, Australia and the Philippines – and in doing so, place a renewed focus on countering Chinese influence in the region.

“US forces won’t simply pack up and go home,” said Wallace.

Beijing must also be wary its longtime ally in Pyongyang doesn’t gravitate toward a new friend in Washington.

“Rapprochement could harm China’s interests if North Korea starts making decisions that prioritize US over Chinese preferences to maintain good ties,” Heath said.

“Like every country in Asia, North Korea has an incentive to seek warmer ties with the US to balance against Chinese power.”

For instance, North Korea might be able to negotiate better trade deals with the US and the West than it currently receives from China, its biggest trading partner.

Sam Roggeveen, an analyst at Australia’s Lowy Institute, says North Korea’s claims to be able to fire nuclear-armed missiles as far as New York or Chicago gives China another advantage, by creating uncertainty between US allies as to whether the US would truly back them up if they were attacked.

Japan and South Korea need to ask themselves, “Would the US risk losing a major city in our defense?” Roggeveen said. “The answer is no.”

China can then, in theory, parlay those doubts into whether the US would come to the aid of Japan in relation to the contested Senkaku/Diaoyu island chain in the East China Sea, or even whether the US would defend Taiwan if China moved on it militarily, analysts say.

Remove those doubts, and the US’ regional alliance becomes more secure, especially when faced with a common threat.

And whereas North Korea is a threat to North Asian countries, China’s influence extends across Asia, potentially drawing more countries into the US’ orbit.

05:01 - Source: CNN
Kim Jong Un reaffirms denuclearization push

But Wallace says there’s one summit outcome that could be a nightmare for both China and the US alliance network – a partial denuclearization where North Korea gives up the long-range missiles that could hit the US mainland but keeps shorter range ones that could still threaten Japan and South Korea.

That could encourage both those US allies to develop their own nuclear arms programs, precipitating an arms race in North Asia.

And there is wide agreement that more nations in the region pursuing nuclear capability would be destabilizing.

“This could have all sorts of cascading effects of which the outcomes are hard to predict,” Wallace said.

05:13 - Source: CNN
The West may be too late to stop Beijing in S. China Sea, says analyst

So what might be the best result for Beijing when the Trump-Kim summit ends?

“A summit which produces nothing tangible, but lowers the temperature” in the region, Roggeveen said.

That’s because with the US preoccupied with the North Korea issue, China can continue what it has been doing for the past several years: fortifying its positions in the South China Sea, increasing diplomatic pressure and military exercises around Taiwan, having its ships and aircraft challenge Japan’s island claims in the East China Sea, and building and modernizing its armed forces, while forging deeper economic ties around the Asia-Pacific.

At the moment, China sees North Korea’s nuclear program to be a “useful tool for its larger purpose,” said Roggeveen, “to undermine America’s claims to be the strategic power in Asia and take that mantle for itself.”

CNN’s Joshua Berlinger contributed to this report.