Still active in the public sphere, he would like to talk about China's current economic conditions and champion further opening-up. But what he did 15 years ago will always define him.

And it is precisely what he did then, that makes his argument now persuasive.

At the luncheon, one of his top concerns was China's talks with the US over a bilateral investment treaty. As many know, the drawing up of a "negative list" is at the center of the talks.

A "negative list" specifies areas that are banned or restricted when it comes to foreign investors. These lists are also pivotal to China's domestic experiment to set up free trade zones.

Long admitted that there is immense pressure against shorter lists. That is not difficult to understand, because shorter lists would take power away from officials sitting in Beijing.

But Long also acknowledged that "without the BIT talks, the domestic 'negative list' can never be really shortened".

He said: "Many domestic issues can only be solved under international pressure. That's been proven over time."

His simple words reverberated. After more than a decade of high-speed growth following the WTO accession, China's growth engine cooled in the past three years. Many domestic and foreign observers lament the lack of a new source of momentum, or what is called the "reform dividend".

They long for a "WTO moment" or a "1992 moment", the latter being the year of late leader Deng Xiaoping's southern tour that ushered in unprecedented entrepreneurial fervor.

I have not had the chance to consult Long on what the next "WTO moment" might be. Is it a BIT with the US? Or domestic FTZs?

But I am sure he would agree that opening-up in China is never inevitable, as many may think.

Unlike smaller countries that would not survive without integrating into the world market, China has a long history and a natural tendency to be introverted and self-indulgent.

Further opening-up requires a push that defies gravity by someone like Long.