A commentary by academic and former diplomat Kishore Mahbubani about small states and foreign policy has drawn criticism from his former colleagues in the Foreign Ministry, as well as Law and Home Affairs Minister K. Shanmugam.
Professor Mahbubani's view in his article, "Qatar: Big lessons from a small country", was described by veteran diplomat Bilahari Kausikan as "muddled, mendacious and indeed dangerous".
Mr Shanmugam, who was foreign minister from 2011 to 2015, said he found the commentary "questionable intellectually".
Also weighing in was Ambassador-at-Large Ong Keng Yong who warned that it is against Singapore's well-being if international relations are based purely on size.
All three took issue with what Prof Mahbubani said was an eternal rule of geopolitics: "Small states must behave like small states."
But the dean of the Lee Kuan Yew School of Public Policy was backed by Dr Yap Kwong Weng, regional adviser on Indochina at the school.
In an e-mail to The Straits Times, Dr Yap said his colleague was merely saying "prudence is required of small states when it comes to geopolitical calculations".
He added that there was nothing dangerous with this line of thinking.
In the commentary published in The Straits Times on Saturday, Prof Mahbubani had mined the diplomatic crisis involving Qatar and its bigger Arab neighbours for lessons there could be for Singapore.
He said Qatar had mistakenly believed it could interfere in affairs beyond its borders because of its wealth, and drew comparisons between this and Singapore's stance on the South China Sea maritime dispute. He added that the late Mr Lee Kuan Yew, who commented "openly and liberally on great powers", was an exception.
"Sadly, we will probably never again have another globally respected statesman like Mr Lee. As a result, we should change our behaviour significantly," he said.
Mr Shanmugam, in a Facebook post, said Prof Mahbubani's assertion is contrary to some basic principles of the founding prime minister that made Singapore successful.
"Mr Lee never advocated cravenness, or thinking small. Did we get to where we are now by thinking "small"? No," he wrote. "That is why Singapore was and is respected, despite being one of the smallest countries in the world. And Singaporeans are proud to be Singaporeans."
Mr Bilahari also took issue with the suggestion that Singapore should behave differently now, saying it is "wrong" and "offensive" not only to Mr Lee's successors but also to all Singaporeans.
He said Mr Lee and Singapore's pioneer leaders were not reckless, but did not hesitate to stand up for their ideals and principles.
He cited examples of how Singapore diplomats held their ground when faced with larger powers, and said: "Singapore did not survive and prosper by being anybody's tame poodle."
But Dr Yap described Mr Bilahari's reply as "exaggerated and unnecessary" and said the diplomat had misconstrued Prof Mahbubani's words.
He added that Prof Mahbubani had not said Singapore should "lay low" and favour larger countries, but instead "reminded us in his article that Singapore should continue to pursue a course that suits the world without trying to behave like a large country".
Said Dr Yap: "As a Singaporean, I don't want our country to be engulfed in large-scale battles that require enormous resources because we can't afford to do so as a small country. This is common sense."
Meanwhile, Mr Ong said in a commentary that Prof Mahbubani's underlying concern seemed to be that Singapore was not exercising enough "savviness" in dealing with the South China Sea issues.
He questioned if that was truly the case, saying: "I personally thought that the thinking South-east Asians respect Singapore's strategic positioning and diplomatic efforts. We have done what is needed based on what we know and the prevailing circumstances."
Mr Shanmugam drew on his own experiences as foreign minister to illustrate his point that small countries should not bow down to larger countries. He said he never forgot that Singapore was a small country, with limits to what it could do.
"But equally I also knew, that once you allow yourself to be bullied, then you will continue to be bullied. And I never allowed myself to be bullied, when I represented Singapore," he added.
In instances where ministers from other countries "threatened us, in different ways, took a harsh tone" when Singapore would not give them what they wanted, Mr Shanmugam said: "As all our foreign ministers have done, I just looked them in the eye and told them we stood firm. They changed their attitude after that."
Singapore must be clear about its interests and go about it smartly, "but not on bended knees and by kowtowing to others", he added.
Almost every country is bigger than Singapore, including its neighbours, he pointed out.
"We treat each other with mutual respect. Once we are shown to be "flexible", then that is what will be expected of us every time," he wrote.
• Additional reporting by Chew Hui Min