LONDON • Of all the policy vows that United States President Donald Trump made and unmade during his long electoral campaign, none has been more prominent or more durable than his promise to forge a new strategic partnership with Russia.

The promise has been repeated so often and in such categorical terms that it has spawned a wave of conspiracy theory explanations. Mr Trump is, supposedly, obsessed with the topic because he's a Russian agent under deep cover, a real-life "Manchurian Candidate", following the example of the character from the famous Cold War movie who was programmed by Russian spies to take over the US. Or, alternatively, that the new US President is being blackmailed by the Russians, who allegedly have compromising material on him.

Yet, there is also a more humdrum and perhaps more persuasive explanation: That the new occupant of the White House genuinely believes in the advantages of friendship with Russia.

Be that as it may, the chances that Russia and the US will join hands in a new strategic partnership remain very slim indeed. For even if they genuinely try, leaders in both Washington and Moscow will soon discover that what they are prepared to offer each other, neither will find very appealing, while the price each partner expects to extract from the other for such a strategic deal will be deemed unacceptable by both sides. This is the story of a divorce slated to occur before the partners even go out on a date, let alone get married.

There was always something very odd about Mr Trump's fascination with Russia, and with Russian President Vladimir Putin.

The two have almost certainly never met face to face, although Mr Trump, just like many other international businessmen who exaggerate their connections in high places, frequently implied that he did.

Furthermore, Mr Putin is hardly a household name in the US; most ordinary American voters have no idea who he is, and those who do recognise the name are unlikely to have a positive opinion of the Russian leader. Meanwhile, Russia itself is not popular in the US, and foreign policy initiatives hardly swing elections.

So, far from being a vote-winner, Mr Trump's repeated pleas for an American partnership with Russia were an electoral liability; as time went by, they became one of the biggest political millstones around Mr Trump's neck. Yet, the Republican candidate persevered in praising "Mr Pyoot'n", as he calls the Russian leader.

MUTUAL ADMIRATION

Mr Trump's admiration for Mr Putin is partly explainable by the broader popularity which the Russian President has enjoyed for years among far-right political circles in the industrialised world.

Within these circles - which Mr Trump also frequented - Mr Putin is seen as a can-do, no-nonsense leader who rejects political correctness, has no difficulty in claiming that Christianity is superior to all other religions, does not know what ethnic diversity is, and believes that gays should remain in the closet, that the poor should remain poor and that "traditional family values" should mean that women stay at home, somewhere between the kitchen and the bedroom.

Whether these are "post-liberal" values, as some Western intellectuals now complain or merely 19th century liberal values as some of Mr Putin's defenders allege, is ultimately immaterial; Mr Putin's ability to reject and defy the current political wisdom by exposing current Western societies as morally bankrupt has made him hugely popular with Western right-wingers.

Mr Trump also has more specific reasons for liking Mr Putin, for the system over which Mr Putin presides is one run by oligarchs, hugely wealthy individuals who blend family, business and politics in every day's work. Mr Putin detests intellectuals and believes that media outlets that do not praise him are merely lying. He also has a real-estate view of international relations: Mr Putin's world is divided between properties he either owns or wants to own, and those owned by competitors.

The similarities between Mr Putin's and Mr Trump's visions are, therefore, compelling. And although the Russian leader has largely kept a polite silence about the US elections, there is little doubt that he views Mr Trump's inauguration as a personal vindication: As seen from Moscow, it's the US political system which is now copying some Russian features, rather than the other way around.

The rise of people like Mr Rex Tillerson, President Trump's nominee for US secretary of state, only reinforces Mr Putin's perception that political trends are now running in his favour, since Mr Tillerson is not just an old partner, but also a master in the business which keeps Russia going: oil and natural gas. Either way, the admiration and perhaps even affection between the top leaders in Moscow and Washington are evidently mutual.

EXPECTATIONS GAP

Yet, this does not mean that they can actually forge a strategic partnership, for there is a huge gap in the expectations of both partners in this putative relationship.

Although Mr Trump has never spelt out in detail what he wants from Moscow, it is clear that there are two tasks for which he deems Russia useful. The first is Russian cooperation to "eradicate completely from the face of the earth" the "radical Islamic terrorism", as Mr Trump put it in his inauguration speech. And the second is eliciting potential Russian support in cornering China, the one power Mr Trump sees as presenting the US with the biggest and most sustained strategic challenge.

Yet, the Russians have very different objectives. Moscow is happy to cooperate with the US on counter-terrorism measures, but sees that as merely a diversion from the top priority, which is to regain for Russia the status as a global power, a country whose support is required in the management of any future world crisis.

And that means an acceptance that Russia should be allowed to have its own spheres of influence in Europe and Central Asia, since without these, it's difficult to see why the US should allow Russia - a country with a population not much bigger than Japan's and an economy not much bigger than that of Italy - a permanent place at the top table.

The continued crisis in Ukraine is largely about getting Western approval for the establishment of a Russian sphere of influence, and Mr Putin has no intention of compromising on this quest.

But at the same time, although the Russians have their own reasons to mistrust the Chinese, they have no intention of cooperating with the US in containing China. That's partly because China will retaliate by challenging the already declining Russian influence in Central Asia, but also because it is in Russia's interest to have a powerful China as a permanent counter-balance to the US.

The Russians may well be tempted to engage in their own China-hedging. Yet, they will do that - and, arguably, are already doing it - with the help of older Russian partners such as India or Vietnam, rather than in conjunction with the Americans, who are always liable to dump the Russians at a later stage by playing the "China card" against Moscow, as the Americans did during the 1970s.

And even if one assumes that America's new president is prepared to put the China question aside and forge a partial strategic deal with Russia over Europe and the Middle East, it's difficult to see how this will be accomplished, or what purpose it will serve.

The US can abandon Ukraine to Russia by simply stopping all economic and military assistance to that country. But it cannot "deliver" Eastern Europe to a Russian sphere of influence even if it wanted to; this is not 1945 when, at the end of World War II, countries were bartered away with the mere whisk of a pen. Nor is it very obvious what the Russians can actually do to eradicate terrorism. The Russian military can drop bombs, but bombs are precisely the commodity Mr Trump does not lack either.

Yet, on almost every other count, the Russians are part of the problem rather than part of the solution to terrorism: Their internal problem with domestic separatists and marginalisation feeds violence, and Russia has one of the highest rates of people volunteering for terrorism. A true Russian counter-terrorism partnership should entail a change in domestic Russian policies, precisely what neither Mr Putin nor Mr Trump is seeking.

In sum, therefore, the Russia-US relationship is one doomed from the start; the partners are not merely incompatible, they don't even understand each other's aspirations, and most certainly have no incentive to address each other's needs.

The only remaining question is whether President Trump wants to pursue this dream or whether, like a good businessman who realises that he's faced with a dud business proposal, he cuts his losses and moves on to other projects.