A former special assistant to the president during the Obama administration says that President Donald Trump’s decision to pull back from a planned summit with North Korea highlights that the president’s foreign policy approach — or lack thereof — has left the United States isolated and at greater risk of war.

Ned Price, who served as special assistant to President Barack Obama and also as a spokesman for his National Security Council, told The Independent that Mr Trump’s decision to cancel the North Korea summit sends a message to foreign allies that the US feels comfortable with unpredictability, even if it strains relationships around one of the most consequential international discussions of modern times.

“This always had to be something that we were in lock-step with our regional allies on. Primarily South Korea, but also China and Japan. This, I think, will be a reminder to all of those countries that Donald Trump's America can't be trusted,” Mr Price said. “Even when we do the right things and make the right moves one day, we may pull the rug out from under them in the next.”

Mr Trump announced that he was pulling out of the planned summit Thursday morning, citing North Korean officials who called Vice President Mike Pence “stupid” for suggesting that the US might pursue a nuclear disarmament agreement similar to the one agreed to by Libya in 2003. The North Korean official also indicated that a nuclear standoff could be on the table if negotiations break down.

The president followed up the withdrawal announcement with a televised address in which he said the US military is “ready if necessary”.

Mr Price said that the major shift could indicate that the White House is struggling to develop a coherent strategy for dealing with North Korea’s nuclear and missiles programmes, and that that lack of clarity is hurting the US internationally.

North Korea Military Parade Show all 6 1 /6 North Korea Military Parade North Korea Military Parade In this image made from video released by KRT on Feb. 8, 2018, a military parade is held at Kim Il Sung Square in Pyongyang, Thursday, Feb. 8 2018, just one day before South Korea holds the opening ceremony for the Pyeongchang Winter Olympics. (KRT via AP Photo) AP North Korea Military Parade This screen grab taken from North Korea's KCTV on February 8, 2018 shows members of North Korea's military taking part in a parade, with missiles being displayed, in Kim Il Sung Square in Pyongyang. North Korea staged a military parade in Pyongyang on February 8 to mark the 70th anniversary of its armed forces, in a show of strength just a day before the Pyeongchang 2018 Winter Olympic Games open in the South. / AFP PHOTO / KCTV / KCTV / -----EDITORS NOTE --- RESTRICTED TO EDITORIAL USE - MANDATORY CREDIT "AFP PHOTO / KCTV" - NO MARKETING - NO ADVERTISING CAMPAIGNS - DISTRIBUTED AS A SERVICE TO CLIENTS - NO ARCHIVESKCTV/AFP/Getty Images AFP/Getty Images North Korea Military Parade In this image made from video released by KRT, North Korean soldiers march during a military parade in Pyongyang, Thursday, Feb. 8 2018. North Korea held a military parade and rally on Kim Il Sung Square on Thursday, just one day before South Korea holds the opening ceremony for the Pyeongchang Winter Olympics. (KRT via AP Photo) AP North Korea Military Parade In this image made from video released by KRT on Feb. 8, 2018, North Korean leader Kim Jong Un, right, inspects honor guards, along with his wife Ri Sol Ju, center, during a military parade in Pyongyang, Thursday, Feb. 8 2018. North Korea held a military parade and rally on Kim Il Sung Square on Thursday, just one day before South Korea holds the opening ceremony for the Pyeongchang Winter Olympics. (KRT via AP Photo) AP North Korea Military Parade In this image made from video released by KRT on Feb. 8, 2018, North Korean leader Kim Jong Un, center, watches the military parade in Pyongyang, Thursday, Feb. 8 2018. North Korea held a military parade and rally on Kim Il Sung Square on Thursday, just one day before South Korea holds the opening ceremony for the Pyeongchang Winter Olympics. (KRT via AP Photo) AP North Korea Military Parade This screen grab taken from North Korea's KCTV on February 8, 2018 shows North Korean leader Kim Jong Un speaking during a military parade in Kim Il Sung Square in Pyongyang. North Korea staged a military parade in Pyongyang on February 8 to mark the 70th anniversary of its armed forces, in a show of strength just a day before the Pyeongchang 2018 Winter Olympic Games open in the South. / AFP PHOTO / KCTV / KCTV / -----EDITORS NOTE --- RESTRICTED TO EDITORIAL USE - MANDATORY CREDIT "AFP PHOTO / KCTV" - NO MARKETING - NO ADVERTISING CAMPAIGNS - DISTRIBUTED AS A SERVICE TO CLIENTS - NO ARCHIVESKCTV/AFP/Getty Images AFP/Getty Images

“There seems to be no strategy. There seems to be no principled approach. It seems to be fly-by-the-seat-of-your-pants every single day, and Trump has tried to convey the notion that unpredictability is a good thing,” Mr Price said. “But, look, you look at where we are, and I think the poof is in the pudding in terms of that: We’re more isolated, we’re more at risk of war, and North Korea still has a nuclear arsenal.”

Mr Trump had planned on meeting with North Korean leader Kim Jong-un in Singapore in June, but the pre-meeting negotiations appeared shaky in the past week or so as the two countries tried to find common ground to start the negotiations.