When pressed on his stance on the controversial deployment of a United States missile shield in a TV debate in March, Mr Moon Jae In did not give a straight answer and infamously replied: "It is necessary to maintain strategic ambiguity."
Elected as South Korea's president two months later, Mr Moon has since changed his tune about the Terminal High Altitude Area Defence (Thaad) system many times, from supporting it to having reservations about it.
Mr Moon has also sent mixed signals on North Korea - from condemnation to offers of dialogue.
Strategic ambiguity - a stark contrast to the previous conservative government's firm commitment to the US and harsh stance towards North Korea - has served the liberal president well, allowing him to hold US and domestic pressure at bay while appeasing China and pushing for engagement with North Korea.
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But calls have grown for Mr Moon to make a stand on various issues, especially after cracks started to show in his dual-track policy of pressure with engagement.
Despite offers of dialogue, Pyongyang has continued to provoke. Last Friday, the North launched its latest intercontinental ballistic missile (ICBM) test, less than a month after its July 4 test. This led Mr Moon to give the go-ahead two hours later to deploy four Thaad launchers, a reversal of an earlier decision to delay the deployment.
Mainstream newspaper JoongAng Ilbo accused the government of doing "somersaults over Thaad", while the English daily Korea Herald said Mr Moon's dual-track strategy is in "peril" after North Korea's second ICBM test last Friday night.
Political rivals also went on the attack. The main opposition Liberty Korea Party criticised his inconsistent North Korea policy; the minor opposition People's Party warned of a "diplomatic disaster" if he continues his "amateurish diplomacy".
Analysts said Mr Moon, who is away on holiday and returns to Seoul on Saturday, will face increasing pressure to adopt a harder stance on North Korea and make a firm decision regarding Thaad, as ambiguity will hurt his credibility.
Seoul National University law professor Lee Jae Min said the Moon administration's bid to balance three major Thaad concerns - US pressure, Chinese objection and protests at home - seems fine in theory, but is not practical in reality.
"It is understandable to take the ambiguous stance because of the response from China and relations with the US. But now, all things are pointing towards one direction, (which is) to take a concrete stance towards North Korea and complete Thaad deployment as soon as possible," said Prof Lee.
"President Moon is reaching the stage where he finally has to make a decision... because of the continued North Korean threat and provocations, the manoeuvring room for him is shrinking very fast."
Ambiguity clouds a separate domestic issue - nuclear power. Mr Moon, who favours a nuclear-free future, shut down a nuclear plant in Busan and ordered the building of two new ones to be stopped.
But he is reconsidering after protests from members of the public and firms fearing the economic fall-out.
While Mr Moon has been accused of pandering to the public, his policy of listening to the people has helped him maintain a high approval rating.
A poll by Realmeter last Friday found that 74 per cent of 2,548 respondents approved of his management of state affairs.
Dr Lee Jae Hyon, from the Asan Institute of Public Policy think- tank, believes the policy of strategic ambiguity can help the Moon government achieve the liberal camp's eventual goal of engagement with North Korea.
The about-turn over Thaad is merely to give the impression that Mr Moon is stern and decisive against North Korean provocation, he added. "In the short term, Mr Moon may be pushed to the right by the US and to the left by China but, at the end of the day, he would achieve what he wants."