Donald Trump took a huge gamble with Kim Jong-un, but was it a risk worth taking?

They came, they saw, they shook hands and exchanged warm words and simply by meeting, they made history.

But as Donald Trump and Kim Jong-un departed from Singapore, having talked for more than four hours and apparently agreed to work towards denuclearisation of the Korean peninsula, it was unclear whether the two countries were on a path to securing a genuine peace deal, or had in essence engaged only in a glorified photo-opportunity.

In a press conference after the working sessions had concluded, Mr Trump sounded optimistic and thanked the 34-year-old North Korean leader “for taking the first bold step towards a bright new future for his people”. Earlier, Kim said the leaders had “decided to leave the past behind” and he vowed: “The world will see a major change.”

Yet though the two men signed a document that was seen by the media pledging to work towards getting rid of nuclear weapons, the details it contained were thin. Shortly before he boarded Air Force One to leave for the US via Guam, President Trump said the US would verify North Korea’s denuclearisation. “We’re going to have to check it. We will check it. Total and complete,” he said.

Trump said he had decided the US should halt military operations on the Korean peninsula, in what would represent a major concession by Washington. China and Russia had proposed such a “freeze for a freeze”, or “dual suspension”, in November, but the US leader then rejected the proposal out of hand.

If implemented, the halting of the joint military exercises would be one of the most controversial moves to come from the summit.

“We will be stopping the war games which will save us a tremendous amount of money, unless and until we see the future negotiation is not going along like it should. But we'll be saving a tremendous amount of money, plus I think it's very provocative,” Mr Trump said.

That being said, by the time Trump’s plane left Singapore US military forces in South Korea had not received any direction to cease joint military drills. “USFK [US Forces Korea] has received no updated guidance on execution or cessation of training exercises – to include this fall’s scheduled Ulchi Freedom Guardian,” US Forces in Korea Lt Col Jennifer Lovett said, in a statement..

His announcement was a surprise even to President Moon Jae-in's government in Seoul. The presidential Blue House said it needed “to find out the precise meaning or intentions” of Mr Trump's statement, while adding that it was willing to “explore various measures to help the talks move forward more smoothly”.

Critics of President Trump said he had given up a lot while receiving little in return. While the summit had given legitimacy to Kim, on whom Trump appeared to lavish praise, the US president had barely raised the issue of human rights. In a bizarre moment, President Trump responded to a question on whether he had betrayed those held in North Korea’s gulags by claiming the tens of thousands of such individuals were among the day’s biggest winners.

Reaction in the US Congress were mixed, but caution seemed the prevailing theme. Senate Republican leader Mitch McConnell called the meeting a "major first step," in U.S.-North Korea relations, but not a decisive one if North Korea does not follow through.

"The next steps in negotiations will test whether we can get to a verifiable deal," Mr McConnell said on the Senate floor. He added, "We and our allies must be prepared to restore the policy of maximum pressure."

Democrats were openly sceptical, saying Mr Trump had already given up some American leverage by committing to halting US military exercises with South Korea.

"President Trump has granted a brutal and repressive dictatorship the international legitimacy it has long craved," Senate Democratic Leader Chuck Schumer said. He pointed out that the Trump-Kim agreement does not define what denuclearization would mean. If nothing else happens, Mr Schumer said the meeting amounts to "purely a reality show summit."

Later, as Mr Trump's plane landed in Guam to refuel, Mr Trump told reporters that he trusted Mr Kim and that he believed the North Korean leader was sincere about his desire for denuclearisation.

“I can only tell you that from the time I’ve (dealt) with him, which is really starting 90 days ago," Mr Trump said. "I think he wants to get it done".

Whether Mr Trump’s gamble has paid off will only be seen in the coming days and weeks. The president said his secretary of state, Mike Pompeo, and national security adviser John Bolton would be following up with Pyongyang next week to press North Korea's commitment to start denuclearisation.

But what precisely does that mean?

“By committing to work 'towards' the denuclearisation of the Korean peninsula, Kim has conceded no more than he did in the 27 April Panmunjom Declaration signed with South Korean President Moon Jae-in,” said Alison Evans, deputy head of Asia Pacific country risk for analysts IHS Markit.

“Rather, the statement implicitly recognises North Korea as a de facto nuclear weapons state. This lends North Korea, and specifically Kim, legitimacy at home and abroad.”

Critics fear that the US has been here before, most notably in 1994 and 2003, when the North Korean regime vowed to give up its weapons programme in return for an easing of sanctions, only to see the nation renege on the deal.

It may be that Trump’s gamble will end up going south. But as the two leaders shook hands and talked on Tuesday in Singapore – something that months ago would have seemed inconceivable – it was hard not to feel it was a risk worth taking.