On 21 July a Russian military Antonov cargo plane landed on an airstrip in Châteauroux, central France. It was loaded with 50 tonnes of humanitarian aid – medical supplies, tents – and flew to Russia’s Khmeimim military base in Syria. This is a stronghold from which Vladimir Putin’s forces have launched relentless attacks on cities and neighbourhoods since 2015, as they threw their military might behind Bashar al-Assad’s brutal regime.

In many ways, this was the moment Emmanuel Macron sold his soul to Putin in Syria. But this awkward mission wasn’t just about France’s image. The entire episode said something about a wider western malaise; about how democracies can too readily sacrifice principles and how authoritarian regimes capitalise on that weakness.

Macron and Putin had agreed to this joint operation during their meeting in May in St Petersburg. According to a Franco-Russian statement, the aid was destined for the people of eastern Ghouta – a suburb of Damascus that has been besieged by Syrian government troops and severely bombed by Russian aircraft. Eastern Ghouta is also where chemical weapons were used by Assad’s forces as recently as April, a crime Russian diplomacy has been busy denying in various international forums. The aid was officially meant to be distributed under UN auspices, but that turned out to be untrue: the UN itself later denied it had been involved. Only the Russian army and Syrian authorities controlled where the medical supplies went.

Macron thinks he's untouchable, but the Benalla scandal could undo him | Pauline Bock Read more

In a nutshell: France allowed itself to be part of a Russia-Syria propaganda stunt that was aimed at showcasing cooperation with a European country whose diplomats had for seven years consistently denounced Assad and Putin’s policies in Syria. Why and how Macron agreed to aid this “humanitarian” gloss to Russia’s involvement in Syria remains unclear.

Unsurprisingly, Kremlin-controlled media such as Sputnik and RT (the very outlets Macron lambasted publicly in 2017) were swift to talk up the news. But in France it received little or no attention. This summer the country is entirely focused on the Benalla scandal (involving a security guard Macron employed, who beat up demonstrators during May Day demonstrations in Paris). But the lack of scrutiny around Macron’s spectacular turnaround in Syria is striking all the same. And at this stage it’s not clear if unpleasant questions will ever be asked. Following a French tradition, Macron’s presidency organises no regular on-the-record briefings, so the Élysée gets to choose when it is publicly held to account.

But the episode’s significance goes well beyond France’s borders. Macron’s duet with Putin in Syria could be a potential harbinger of more western capitulations over Syria, a human rights catastrophe in which an estimated half a million people have been killed and millions made refugees. Through this ill-advised action, France became the first western democracy to allow itself to be used in an exercise of high-level Russian spin – hardly a small gain for Putin.

Play Video 0:35 French president Macron claims he guided Trump on Syria - video

Perhaps you are wondering what is wrong with providing aid through the Russian army? The answer is in the question: even as a one-off operation, it is morally debasing. Not least because there was no guarantee the aid would reach the right people, or that it would not partly benefit forces that have massacred local populations.

The gesture of transferring aid to the Russian military condoned its presence on the ground – along with the Syrian organisations working with it – as a credible conduit for relief. This from a country, France, whose representative in the UN in January was rightly asking what credibility could possibly be given to Syrian government statements or to those who support them.

“Syria fatigue” set in long ago in western societies. It draws on a sense of powerlessness in the face of seemingly unstoppable horror and intractable complexity. Confusion and complacency have also been deepened by the spread of far-right ideas (bear in mind that Italy’s Matteo Salvini, France’s Marine le Pen, Austria’s Freedom party, and others, all approve of Putin’s actions in Syria) as well as the what-aboutery of the far left.

It doesn’t help, of course, that the US president consorts with autocratic foreign leaders who exploit his narcissism and shallowness, nor that his one and only goal in Syria seems to be to protect Israel from the Iranian regional threat – entirely indifferent as he is to the suffering of Syrian civilians.

Play Video 0:54 Russia opposes western resolution on Syria at UN – video

But France had in recent years maintained a firm position on Syria’s bloodbath and Russia’s role in it. Now that the Élysée has in effect whitewashed the Russian military, it has taken the risk of abrogating whatever humanitarian principles upheld its choices – and that makes it look morally bankrupt. To what purpose? One explanation, suggested by sources in Paris, is that Macron wants to “stay in the diplomatic game” on Syria. With Donald Trump proving such an unreliable ally on Syria as on other issues, Macron seems to have concluded that he needs to get closer to Putin.

Putin has certainly played his cards well in Syria,catching the west off-guard, and taking the upper hand militarily alongside Iran, Assad’s other key ally. Now that the last remnants of the 2011 anti-Assad popular uprising are being methodically crushed, he is intent on recruiting western support for so-called reconciliation plans, as well as western contributions to Syria’s “reconstruction”, all of which would take place under Russia’s control. It’s one thing for Europeans to be realistic about a dire imbalance of forces and to try to build a strategy aimed at preventing the worse-case scenario of yet more repression and radicalisation in Syria, still a potential breeding ground for terrorism. But it is very different to pretend Russia can be an ally in humanitarian matters, after its key role in the mass atrocities that have occurred, and after multiple vetos and other diplomatic obstructions at the UN.

Syrian government forces seal victory in southern territories Read more

Macron’s presidency is racked by the fallout from the Benalla case. But this is another scandal, that ought to be closely looked into, regarding how a key European democracy responds to crimes against humanity and those who have helped perpetrate them on a mass scale. Putin is seeking western complicity in his cover-up of atrocities in Syria. He is seeking to rewrite recent history by drawing western countries into a narrative that casts Russia as a potential force for good rather than as the murderous accomplice of Assad.

Recently Putin even went as far as mentioning Europe’s refugee problem as a further reason for the west to cooperate with him and with Assad, who has every intention of staying in power. This at a time when the Syrian regime has admitted to having tortured thousands to death in its prisons since 2011.

The question now for European countries is whether they will willingly follow in Macron’s footsteps and become pawns in Putin and Assad’s game to secure validation as a first step towards securing western funds for reconstruction.

Macron is a young French president who wants to lead Europe, and who has often displayed his taste for philosophy. As he courts Putin in the hope that it will help prevent France getting sidelined in Syria, he might want to consider what one philosopher, Reinhold Niebuhr, had to say about “the irony of history”. The irony, wrote Niebuhr, comes when “our dreams of pure virtue are dissolved” as a result of “taking morally hazardous action” and “courting prospective guilt”.

• Natalie Nougayrède is a Guardian columnist