In an interview on board his RAF VC10 from Singapore, Mr Cook argued that Britain cannot do it alone: "The pressure we apply on a country like Indonesia will only work if it's part of a co-ordinated pressure from other countries." Certainly, there are no miracles on the horizon. The government in Indonesia was hardly rocked to its foundations by Mr Cook's visit. Instead, the Indonesian Foreign Minister talked suavely of "concrete co-operation" between Britain and Indonesia, "especially in the field of human rights".
In Malaysia, implied criticism of the government's stance on human rights was firmly rejected. Malaysia's determination not to be pushed around became even clearer yesterday, when it defied Mr Cook by insisting - as reported above - that Burma should come to the Asia-Europe Meeting (Asem) in London next year.
In Singapore, where press freedom is an important and controversial issue, Mr Cook appeared only to have raised the matter with his hosts after journalists asked about it at his final press conference.
In other words, this was not a trip of grand confrontation. Mr Cook studiously avoided saying the kind of things which might make him persona non grata. This can be perceived as weaselling out - or as playing a long game. Mr Cook believes that "it is a question of finding a balance", and insists it is better not to be seen to wield a big hammer. "What I said on human rights was listened to, because it was not a lecture ... I would strongly contest the suggestion that I've backed off in any way," he told The Independent.
He is determined that the issues of trade and human rights should not be seen as an either-or. Mr Cook seemed close to bottling out of direct confrontation, at some points - as though he had been Sir Humphreyed out of his proclaimed commitment to human rights. And yet, historical comparisons make it clear that the trip cannot be written off as irrelevant grandstanding, or as pinpricks in an elephant's hide.
In 1975, the Soviet Union signed up to a raft of human rights guarantees - and then ignored those commitments. At the time, the Helsinki accords were regarded by many in the West as a cop-out, because the West had no way of forcing Moscow to comply. In reality they provided a benchmark which helped the democratic opposition throughout the Soviet bloc. The commitments were modest, but laid the foundation for enormous change, in the years to come.
There is no certainty that Mr Cook's mission will seem successful. It is also clear the most difficult challenges are yet to come. On Saudi Arabia, for example - a rich and powerful ally, whose track record on human rights makes Indonesia seem a democratic nirvana - Mr Cook refuses to be drawn. After all, he points out, he has only just finished a trip to South-East Asia: isn't that enough? One of these days, however, he will have to comment. It will not be easy.
Mr Cook himself is upbeat about the future, because of the experience of recent decades. "When I was young, Latin America was all military dictatorships. Now, it's democratic. Africa, ditto. In the Philippines, it's just 10 years since it was transformed." The same kind of change, he believes, could come to Indonesia and other countries in the region.
"I think it is particularly important to apply these constant pressures to the next generation who are likely to take over [from 76-year-old President Suharto] - so that they understand that if they want an outward-looking Indonesia, they have got to adopt a different style."
Mr Cook was scathing about the "easy apocalpytic" assessments of the the south-east Asian tiger economies. The region's markets have gone through enormous turbulence in recent days and weeks.
"Any idea that this is the end of South-East Asia as an economic force is jejune ... Broadly speaking, there is going to be a return to a strong trend of economic growth."