It was one of the defining moments of the "triangular diplomacy" conceived by Henry Kissinger and Richard Nixon, the point at which the US President touched down in what Westerners then called Peking to meet Chinese premier Chou En-lai.

Differences were set aside so China might join the comity of nations.

"Salmond in China" doesn't have quite the same ring to it, but as the First Minister makes his fourth visit this week a similar pragmatism is at play. For the SNP leader realises when it comes to what the Prime Minister calls a "global race", China is in the lead. Securing a place in its wake for Scotland (independent or otherwise) is an obvious strategy. Today the First Minister will hold talks with state councillor Yang Jie Chi, China's principal foreign minister.

In advance of his visit, Mr Salmond was typically effusive, hailing a "wonderful country" and extending his best wishes to "the people of China", not least because Scottish exports to the country have risen by 45% since the Scottish Government published its China Plan in 2006. The most recent incarnation of that strategy document even refers to "shared values".

Formally, of course, none of this constitutes foreign policy, for that is the preserve of the Foreign and Commonwealth Office in London. Nor is it anything new. The engagement with China began under Jack McConnell who, as First Minister, also pursued links - even in the form of international aid - with Malawi, work he continues from the Upper House.

And although the current First Minister pre-empted obvious criticism about engaging with what is,whatever its economic prowess, an undemocratic and frequently authoritarian government by meeting human rights organisations prior to his five-day trip, this growing Sino-Scottish relationship nevertheless makes it harder to occupy the moral high ground.

Last summer, for example, Mr Salmond declined to meet the Dalai Lama during a private visit to Scotland. The First Minister refused to say if the matter had been raised on meeting China's ambassador to the UK Liu Xiaoming (it had), and when asked if his meeting Tibet's spiritual leader might have threatened Chinese investment in Scotland, Mr Salmond replied: "We do what is appropriate for the benefit of the Scottish people."

Doubtless he meant securing trade, jobs and therefore economic growth for "the Scottish people", but is that to be pursued no matter what the democratic and humanitarian context? Mr Salmond is of course a pragmatist and, if pushed, would no doubt concede the point, but for the leader of a centre-left party championing the self-determination of small nations, it's a curious place to be.

Last week, the First Minister again declined to say whether he would meet the exiled Tibetan leader.

By contrast the UK Government, often lambasted by the SNP for lacking moral fibre both at home and abroad, is sticking to its line on human rights in China. "We will be respectful. But we will be consistent," said Foreign Office Minister Hugo Swire last week. "And we're not resigning from anything we've ever said on human rights."

This followed reports in the Communist Party's People's Daily newspaper that UK ministers had confessed to "mishandling" relations with Tibet (David Cameron's willingness to meet the Dalai Lama led to his being snubbed in Beijing). Mr Swire said he and his colleagues "didn't recognise" that version of events.

To date, Mr Salmond's interventions on human rights in China have been token at best. There's also the case of Taiwan, which I visited early last week. Every day pro-independence demonstrators march around the Ximen area of Taipei displaying banners urging its government to abandon "China-centrism" and establish "a Free Democratic STATE'" (which, in an interesting echo of Scotland's own movement, campaigners say would create "a Social Equality"). "Do you think China and Taiwan are the same thing?" one asked me. "No," I replied, "of course not." He beamed; it was the right answer.

To all intents and purposes, Taiwan is already an independent nation; what its "independence" campaigners desire is international recognition, something withdrawn as a result of Mr Nixon's diplomatic coup 41 years ago (until then Taiwan, rather than the People's Republic of China, occupied a permanent seat on the UN Security Council). Currently, only around 20 countries recognise Taiwan, mainly small islands and Central American republics.

Where, I found myself wondering, does the SNP stand on Taiwanese independence? If sovereignty is a compelling requirement for Scotland within the UK (a largely democratic country with a pretty good human rights record), what then is the argument against the same for Tibet and Taiwan? Of course, the party's position is "no comment" rather than outright opposition, but the question still stands.

All of which demonstrates the danger of making sweeping points about sovereignty. If independence is truly a "natural state of affairs" then the SNP would find itself in all sorts of tricky diplomatic situations. Arguing that those within a country are best placed to govern that nation's affairs is similarly problematic. For a few moments last week I set foot in the Democratic People's Republic of Korea - could such an argument seriously be applied to those occupying the authoritarian north of the peninsula?

I also visited the tiny Sultanate of Brunei, which was still a British Overseas Territory within my lifetime and will shortly mark (or perhaps not) 30 years of independence. The Sultan was not exactly thrilled about breaking the link with the UK, but broken it was; mementos of his time at Sandhurst still have pride of place in Bandar Seri Begawan city's Royal Regalia Museum. Again, the blanket rules of independence don't quite apply.

But then, it's safe to say foreign policy is not one of the SNP's strong points, particularly in the context of the referendum debate. M Salmond has stuck to vague generalities about an independent Scotland being "determined to be good world citizens", prompting the former SNP candidate (and British Army officer) Stuart Crawford to observe that the SNP didn't have a foreign policy "apart from being nice to everybody".

But being "nice" only takes a nation so far. As Charles de Gaulle once observed, no nation has friends, only interests. In that context the First Minister is continuing a long tradition of foreign policy ( and indeed, this week's trip is undoubtedly intended to project him as a statesman ahead of the referendum). Be it whisky, salmon or education, Mr Salmond is pursuing Scotland's interests in the Far East.

Labour's Shadow Foreign Secretary Douglas Alexander recently spoke of the need for an "Asian step-change" in British foreign policy, engaging with China on a range of issues from climate change to international crisis management.

Perhaps Scotland's First Minister is ahead of the curve, but as China's economy forges ahead, questions over its democratic and humanitarian values can only grow louder.

What of China's interest in Scotland? As ever, realpolitik is at play, just as there was when Mr Nixon played one Cold War superpower off against the other. As a recent editorial in the Global Times (another Chinese government mouthpiece) observed, "cultivating more contacts with separatists" in Scotland "would make London quite uncomfortable". And that, of course, is hardly likely to bother the First Minister.