How do you take a great relationship and make it "fantastic-er"?

That was the challenge that departing United States Ambassador Kirk Wagar faced during his 3½ years in Singapore.

The 47-year-old lawyer by training cannot be faulted for not trying. Blessed with boundless energy, a hail-fellow-well-met demeanour, boyishly cropped hair and a penchant for clothes that tend to need volume control, his enthusiasm to build ties has often been infectious to his circle of friends and associates here.

In some ways, the work could not have been too difficult. Few Asian states, not even treaty allies of the US, like Thailand and the Philippines or even Japan, are as welcoming of America as Singapore has consistently been. Security coordination between the two is intense. Much military weaponry, particularly in the Singapore Air Force, is bought from the US. The fireworks at the American community's Fourth of July celebrations here (Mr Wagar held one Independence Day anniversary on Sentosa Beach) often seem as noisy as those on Singapore's National Day.

Little surprise there. American companies are some of the largest employers on the island - by Mr Wagar's calculation, the top 10 US companies here, including Citibank, Seagate, Hewlett Packard and ExxonMobil - employ as many as half the people on the rolls of the Singapore Government.

Still, there is always the danger of taking a relationship for granted.

How, then, do you make it "fantastic-er" - to borrow Mr Wagar's own phrase? Perhaps, as the advertisement for Old Parr whisky goes, with more of the same. And then some.

Last year, US President Barack Obama did precisely that by putting on a state dinner for Prime Minister Lee Hsien Loong at the White House. That it was only the 12th such event he had hosted in the eight years he occupied the place - by some calculations, Mr Obama had 300 rounds of golf in the same period - underscores the value he places on the relationship with Singapore.

The last time a Singapore leader had been thus honoured was more than three decades ago, when founding prime minister Lee Kuan Yew paid a visit.

How does one swing such a prestigious event for the leader of your host nation? A lot depends on your relationship with the boss. America has two types of ambassadors - the career diplomat and the political appointee. Typically, an American president sends trusted confidants to critical posts. In Asia, they include the US envoys to China, Japan, India and Singapore. Mr Wagar, like Mrs Caroline Kennedy in Tokyo, is a political appointee.

It helps the relationship, therefore, that Mr Wagar is chummy with Mr Obama, has his mobile number and helped him win Florida, one of America's most vote-rich states, during his successful runs for the presidency.

Mr Wagar acknowledges that he "knows the President" but says he is given too much credit for the state dinner, adding that Singapore ambassador to Washington Ashok Mirpuri worked equally hard to make it happen. In any case, the austere Mr Obama would not have consented if he had not wanted to.

"The reality is that President Obama has a genuinely (close) relationship with Mr Lee and he wanted to make a statement about him and Singapore," says Mr Wagar. "You see that closeness at international summits. The two are often in a corner, talking, sometimes laughing. There is genuine affection and respect between them."

Born in Canada, Mr Wagar arrived in the US as a student at age 18. He stayed on because he enjoyed "the hustle and bustle of the United States as a teenager involved in anti-apartheid activity and stuff like that. It stuck with me how things moved when America took it up as an issue. America was in every conversation".

Most of his years since have been spent in the Miami area and he was running a successful law practice when he got the "opportunity to serve", as he calls it. That meant giving up his law practice. His wife Crystal, a lawyer with her own practice in Miami, tried to run her firm from Singapore but gave it up eventually. Mr Wagar takes satisfaction in seeing the bilateral relationship during his term widening into regional projects, cyber and port security and combating extremism.

This week, for instance, a group of Singaporean law enforcement officers is in the US for training in handling an active shooter rampaging in a mall or school. In turn, the US instructors gain perspective on the challenges in this part of the world.

The private sectors are jointly reaching out to new parts of the world, including Latin America, offering expertise on smart cities, financial technology and other things. Meanwhile, Singapore was the seventh country to gain access to the US Global Entry Programme, easing travel into the US for Singaporeans.

US influence in the region

Mr Wagar's term has coincided with some remarkable geopolitical shifts but he bristles at the suggestion that US influence in the region is waning, saying there is no evidence to support that thesis.

Politically, economically and militarily, America is more deeply engaged in Asia than ever before. It had signed Asean's Treaty of Amity and Cooperation, appointed its first ambassador to Asean and was invested more in the region than any other nation. Ties with Vietnam have been normalised.

Neither is America in decline, he insists. "Somebody said America has had a good run but the next Microsoft will come out of China. I do not believe that will be the case. If you walk into Apple today, maybe only half are American passport holders, let alone born in the US. But the other 50 of the best and the brightest are attracted to America because of our institutes of higher learning, our freedom and our fun. We are a long way from being perfect but show me another country that is as attractive."

Perhaps it was ordained that Mr Wagar, whose wife is African-American, should have been appointed to Singapore, a multiracial nation of immigrants, much like his own adopted country.

While he did not specifically request to be posted here, it was at the top of the list of options the White House put on the table, and the Wagars happily accepted.

His education about Singapore began even before he got here, thanks to his friendship with Mr Steven Green, the former boss of Samsonite Corp, who served as US ambassador here between 1997 and 2001 and built up a close relationship with the senior Mr Lee and his son.

Mr Wagar says the stint here was like doing an MBA or a doctoral thesis on one of the most important regions of the world, expertise he wants to put to use in the next stage of his career. And he endorses the words of Mr Philip Green, his peer at the Australian High Commission, who completed his tour of duty a few weeks ago.

"There are many important cities around the world but my belief is, Singapore is the place where the greatest conversations are taking place right now," he says.

The last few weeks have been a period of reflection.

It is hard to explain to people at home what it was like to be here for the celebration of Mr Lee Kuan Yew's life, bookended by the celebration of the remarkable journey of President S R Nathan, envoy to Washington during the tense time when Singapore caned American teenage vandal Michael Fay. (Mr Lee died in March 2015; Mr Nathan in August last year).

Mr Wagar's first meeting with the senior Mr Lee was the one time he lost his natural jauntiness, making him feel he was going for an "oral examination for a job I was not sure I was qualified for". Already close to 90, Mr Lee was frail in body but, while he often paused for breath, his mind was perfectly alert.

"We all have our hour and our season, but the hour I spent with Lee Kuan Yew was one of the most stressful of my professional life. I felt I was being tested a bit, prodded and also directed and taught - about Singapore, the region and America's role in what had been and what could be. I didn't want to embarrass myself, lest the word get out that he thought this guy was a waste of time."

Mr Nathan, on the other hand, was exceptionally kind to him and Mrs Wagar.

He adds: "To think I am the last US ambassador to have a personal relationship with Mr Lee and Mr Nathan is really humbling."

Orderly, focused Singapore, of course, has its way of influencing anyone who has lived here for a while. Take the din about needing more babies, for instance. Two of the Wagar children, Rhys and Avery, were born during his stint here.

Mr Wagar's friends are relieved that his shoes are better matched with his suits these days, although he won't concede that his sartorial style was ever loud. "It's just that I don't have boring socks."

When he went to make his farewell call on Mr Lee Hsien Loong this month, he wore a suit that raised eyebrows in the PM's private office - for a different reason.

"Very conservative today, eh?," remarked a top aide to Mr Lee, smiling at Mr Wagar's sober navy blue jacket and trousers.