TOPSHOT - US President Donald Trump (R) poses with North Korea's leader Kim Jong Un (L) at the start of their historic US-North Korea summit, at the Capella Hotel on Sentosa island in Singapore on June 12, 2018. - Donald Trump and Kim Jong Un have become on June 12 the first sitting US and North Korean leaders to meet, shake hands and negotiate to end a decades-old nuclear stand-off. (Photo by SAUL LOEB / AFP)        (Photo credit should read SAUL LOEB/AFP/Getty Images)
SAUL LOEB/AFP/AFP/Getty Images
TOPSHOT - US President Donald Trump (R) poses with North Korea's leader Kim Jong Un (L) at the start of their historic US-North Korea summit, at the Capella Hotel on Sentosa island in Singapore on June 12, 2018. - Donald Trump and Kim Jong Un have become on June 12 the first sitting US and North Korean leaders to meet, shake hands and negotiate to end a decades-old nuclear stand-off. (Photo by SAUL LOEB / AFP) (Photo credit should read SAUL LOEB/AFP/Getty Images)
Now playing
02:08
Is North Korea denuclearization happening?
CNN
Now playing
02:52
Trump: Kim Jong Un has been open, terrific
Pleiades © CNES 2018, Distribution Airbus DS
Now playing
01:08
New North Korea images spark concern
US Secretary of State Mike Pompeo (3rd L) shakes hands with North Korea's Foreign Minister Ri Yong Ho (3rd R) as they arrive for a group photo at the ASEAN Regional Forum Retreat during the 51st Association of Southeast Asian Nations (ASEAN) Ministerial Meeting (AMM) in Singapore on August 4, 2018. - Leaders, ministers and representatives are meeting in the city-state from August 1 to 4 for the ASEAN Ministerial Meeting (AMM). (Photo by Mohd RASFAN / AFP)        (Photo credit should read MOHD RASFAN/AFP/Getty Images)
MOHD RASFAN/AFP/AFP/Getty Images
US Secretary of State Mike Pompeo (3rd L) shakes hands with North Korea's Foreign Minister Ri Yong Ho (3rd R) as they arrive for a group photo at the ASEAN Regional Forum Retreat during the 51st Association of Southeast Asian Nations (ASEAN) Ministerial Meeting (AMM) in Singapore on August 4, 2018. - Leaders, ministers and representatives are meeting in the city-state from August 1 to 4 for the ASEAN Ministerial Meeting (AMM). (Photo by Mohd RASFAN / AFP) (Photo credit should read MOHD RASFAN/AFP/Getty Images)
Now playing
01:49
Pompeo delivers Trump's letter to N. Korea
TOPSHOT - US President Donald Trump (R) poses with North Korea's leader Kim Jong Un (L) at the start of their historic US-North Korea summit, at the Capella Hotel on Sentosa island in Singapore on June 12, 2018. - Donald Trump and Kim Jong Un have become on June 12 the first sitting US and North Korean leaders to meet, shake hands and negotiate to end a decades-old nuclear stand-off. (Photo by SAUL LOEB / AFP)        (Photo credit should read SAUL LOEB/AFP/Getty Images)
SAUL LOEB/AFP/AFP/Getty Images
TOPSHOT - US President Donald Trump (R) poses with North Korea's leader Kim Jong Un (L) at the start of their historic US-North Korea summit, at the Capella Hotel on Sentosa island in Singapore on June 12, 2018. - Donald Trump and Kim Jong Un have become on June 12 the first sitting US and North Korean leaders to meet, shake hands and negotiate to end a decades-old nuclear stand-off. (Photo by SAUL LOEB / AFP) (Photo credit should read SAUL LOEB/AFP/Getty Images)
Now playing
02:11
UN: N. Korea still pursuing missiles program
TOPSHOT - 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. - Donald Trump and Kim Jong Un became on June 12 the first sitting US and North Korean leaders to meet, shake hands and negotiate to end a decades-old nuclear stand-off. (Photo by Anthony WALLACE / POOL / AFP)        (Photo credit should read ANTHONY WALLACE/AFP/Getty Images)
ANTHONY WALLACE/AFP/AFP/Getty Images
TOPSHOT - 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. - Donald Trump and Kim Jong Un became on June 12 the first sitting US and North Korean leaders to meet, shake hands and negotiate to end a decades-old nuclear stand-off. (Photo by Anthony WALLACE / POOL / AFP) (Photo credit should read ANTHONY WALLACE/AFP/Getty Images)
Now playing
02:25
Pompeo: Kim Jong Un not acting consistently
Airbus Defense and Space
Now playing
01:44
New images show N. Korea dismantling test site
CNN
Now playing
01:32
Clarke: Trump diminishes US role and influence
Now playing
01:16
Source: N. Korea seeking 'bold move' from US
Now playing
02:07
Trump privately expressed N. Korea frustration
Photo Illustration/Getty images
Now playing
02:01
North Korea officials skip meeting with US
SINGAPORE, SINGAPORE - JUNE 12:  In this handout photograph provided by The Strait Times, North Korean leader Kim Jong-un (L) with U.S. President Donald Trump (R) during their historic U.S.-DPRK summit at the Capella Hotel on Sentosa island on June 12, 2018 in Singapore. U.S. President Trump and North Korean leader Kim Jong-un held the historic meeting between leaders of both countries on Tuesday morning in Singapore, carrying hopes to end decades of hostility and the threat of North Korea's nuclear programme. (Photo by Kevin Lim/The Strait Times/Handout/Getty Images)
Kevin Lim/The Strait Times/Handout/Getty Images
SINGAPORE, SINGAPORE - JUNE 12: In this handout photograph provided by The Strait Times, North Korean leader Kim Jong-un (L) with U.S. President Donald Trump (R) during their historic U.S.-DPRK summit at the Capella Hotel on Sentosa island on June 12, 2018 in Singapore. U.S. President Trump and North Korean leader Kim Jong-un held the historic meeting between leaders of both countries on Tuesday morning in Singapore, carrying hopes to end decades of hostility and the threat of North Korea's nuclear programme. (Photo by Kevin Lim/The Strait Times/Handout/Getty Images)
Now playing
01:28
Trump touts North Korea denuclearization
SINGAPORE - JUNE 12: In this handout photo, North Korean leader Kim Jong-un shakes hands with U.S. President Donald Trump during their historic U.S.-DPRK summit at the Capella Hotel on Sentosa island on June 12, 2018 in Singapore. U.S. President Trump and North Korean leader Kim Jong-un held the historic meeting between leaders of both countries on Tuesday morning in Singapore, carrying hopes to end decades of hostility and the threat of North Korea's nuclear program. (Photo by Kevin Lim/THE STRAITS TIMES/Handout/Getty Images)
Handout/Getty Images AsiaPac/Getty Images
SINGAPORE - JUNE 12: In this handout photo, North Korean leader Kim Jong-un shakes hands with U.S. President Donald Trump during their historic U.S.-DPRK summit at the Capella Hotel on Sentosa island on June 12, 2018 in Singapore. U.S. President Trump and North Korean leader Kim Jong-un held the historic meeting between leaders of both countries on Tuesday morning in Singapore, carrying hopes to end decades of hostility and the threat of North Korea's nuclear program. (Photo by Kevin Lim/THE STRAITS TIMES/Handout/Getty Images)
Now playing
01:56
Kim Jong Un snubbed Mike Pompeo, source says
U.S. Secretary of State Mike Pompeo, left, speaks during a meeting with North Korean Director of the United Front Department Kim Yong Chol at the Park Hwa Guest House in Pyongyang, North Korea, Friday, July 6, 2018. Pompeo is on a trip traveling to North Korea, Japan, Vietnam, Abu Dhabi, and Brussels. (AP Photo/Andrew Harnik, Pool)
Andrew Harnik/AP
U.S. Secretary of State Mike Pompeo, left, speaks during a meeting with North Korean Director of the United Front Department Kim Yong Chol at the Park Hwa Guest House in Pyongyang, North Korea, Friday, July 6, 2018. Pompeo is on a trip traveling to North Korea, Japan, Vietnam, Abu Dhabi, and Brussels. (AP Photo/Andrew Harnik, Pool)
Now playing
02:09
N. Korea to Pompeo: You may not have slept well
WASHINGTON, DC - MAY 09:  National Security Adviser John Bolton speaks on a morning television show from the grounds of the White House, on May 9, 2018 in Washington, DC. Yesterday President Donald Trump announced that America was withdrawing from the Iran nuclear deal.  (Photo by Mark Wilson/Getty Images)
Mark Wilson/Getty Images
WASHINGTON, DC - MAY 09: National Security Adviser John Bolton speaks on a morning television show from the grounds of the White House, on May 9, 2018 in Washington, DC. Yesterday President Donald Trump announced that America was withdrawing from the Iran nuclear deal. (Photo by Mark Wilson/Getty Images)
Now playing
01:34
Bolton: US has plan for denuclearizing N. Korea
U.S. Secretary of State Mike Pompeo, second from right, greets Kim Yong Chol, second from left, a North Korean senior ruling party official and former intelligence chief, as they arrive for a meeting at the Park Hwa Guest House in Pyongyang, North Korea, Friday, July 6, 2018. Pompeo is on a trip traveling to North Korea, Japan, Vietnam, Abu Dhabi, and Brussels. Also pictured is Andrew Kim, the head of the CIA's Korea Mission Center, right. (AP Photo/Andrew Harnik, Pool)
Andrew Harnik/AP
U.S. Secretary of State Mike Pompeo, second from right, greets Kim Yong Chol, second from left, a North Korean senior ruling party official and former intelligence chief, as they arrive for a meeting at the Park Hwa Guest House in Pyongyang, North Korea, Friday, July 6, 2018. Pompeo is on a trip traveling to North Korea, Japan, Vietnam, Abu Dhabi, and Brussels. Also pictured is Andrew Kim, the head of the CIA's Korea Mission Center, right. (AP Photo/Andrew Harnik, Pool)
Now playing
02:43
Trump touts confidence in Kim Jong Un
(CNN) —  

President Donald Trump took a huge risk by holding a summit with North Korean leader Kim Jong Un and hailing it as a stunning history-changing success.

Now, with diplomacy with Pyongyang at an impasse and tensions rising, the payout for that gamble may be coming due.

The world is not yet back to the brinkmanship and “fire and fury” rhetoric between Trump and the isolated state that sparked fears of a slide to war last year.

But if rising angst between the US and North Korea turns into a more permanent fracture of the diplomatic initiative that peaked with June’s summit between Trump and Kim in Singapore, fears of a conflict that could kill millions on the Korean Peninsula might return.

Apart from the human and geopolitical stakes, Trump would face an acute, personal political embarrassment if the prestige he has invested in the process turns out to have been for nothing. And Republican leaders, keen to paint him as a statesman with difficult midterm elections looming, could become collateral damage.

But the lack of progress is alarming many seasoned Washington foreign policy leaders, and may be a direct result of the lack of ironclad commitments won by the President in Singapore.

“I think we are back at a very tense moment,” David Petraeus, the former Iraq War general and CIA director, said Tuesday on CNN’s “New Day.”

“I think, frankly, that the declaration that was achieved back when the President and Chairman Kim met was probably vaguer than one would have hoped. Denuclearization doesn’t mean the same thing to us as it means to them.”

The weeks since the summit have tested Trump’s diplomatic credibility.

Since he returned home from Singapore boasting that he had removed the North Korean nuclear threat, Kim has taken few meaningful steps toward denuclearization. North Korea appears to be pressing ahead with the production of missile and nuclear material and has not given an accounting of its weapons programs that would be the basis for any meaningful disarmament process.

Last week, Trump suddenly ordered Secretary of State Mike Pompeo not to make a fourth visit to Pyongyang, throwing the diplomatic situation into yet more turmoil. CNN reported that North Korea had sent the administration a letter warning that diplomacy “may fall apart.” The letter, which was first reported by The Washington Post, left the diplomatic process on a precipice and took the President closer to a looming decision point on whether to crank up political and military pressure on Kim or to offer concessions to pick the deadlock.

The latest developments have also put Trump in a tough political position, as critics argue that his naivete in holding a summit with no preconditions, in the absence of a planned out diplomatic process with a ruthless and resourceful foe, has backfired.