Russia will vote in presidential elections next month that Vladimir Putin is certain to win. Consider that statement for a moment. An election implies a contest. So how can the current president, who has already served three terms and wielded power in the Kremlin continuously since 1999, be assured of victory in advance?

The answer is that Russia’s is an election in name only. In truth it is a sham and a smokescreen, designed to confer democratic respectability on to a corrupt oligarchy. For Russians accustomed to unaccountable rule from on high, this is nothing new. More surprising is the supine acquiescence, bordering on complicity, of western democracies.

Putin will win on 18 March because the system he created, politely known as “managed democracy”, removes all elements of surprise. His most credible challenger, Alexei Navalny (who in any case did not expect to win), has been banned from participation on specious legal grounds. Last month Navalny was arrested while urging an election boycott.

This silence contrasts sharply with oft-stated British concerns about upholding democracy in Africa and elsewhere.

Putin’s control of Russia’s television outlets and other media means political opponents are virtually invisible, unless they are in court on a charge. By contrast, his own public appearances receive fawning blanket coverage.

There are no presidential debates, no unsanctioned opinion polls. Rival candidates do exist, but they resemble sparring partners whose task is to legitimise the process while helping the champ show off his best punches. They include Vladimir Zhirinovsky, a sort of ultra-nationalist Screaming Lord Sutch, and Pavel Grudinin, the Communist party’s candidate, who runs a privatised company called Lenin State Farm.

Ksenia Sobchak, a liberal, pro-gay rights former reality TV host, claims to offer an alternative to Putinism. But her wealthy establishment background has prompted the dismissive nickname “Russia’s Paris Hilton”. When Sobchak recently visited Grozny, stronghold of the Chechen warlord and Putin ally Ramzan Kadyrov, police harassed her and gangs of men shouted that she resembled a horse.

Facebook Twitter Pinterest Ksenia Sobchak. Photograph: Saul Loeb/AFP/Getty Images

Political theatre aside, Putin, projecting strength and continuity, knows he will win by a landslide. The fix is in. No other result is imaginable – or allowable. His main concern, analysts say, is achieving a high turnout and a big victory margin, surpassing the 64% he gained six years ago. He also wants an ostensibly free and fair election to boost his international credibility – and no repeat of the 2012 street protests.

In other words, Putin wants it both ways: a genuine electoral contest and a no-risk, hands-down victory. And so far, he seems to be succeeding.

If this rigged election were being held in Iran or Zimbabwe or Venezuela, screams of tweeted outrage would issue daily from the White House. But Donald Trump is strangely silent. Why? Everybody knows he has a soft spot for the hard man in the Kremlin. There are numerous personal, business and political crossovers. Some are the subject of a federal investigation.

But even by Trump’s standards, the current administration’s behaviour is contemptible. Rather than condemning Navalny’s harsh treatment and Russia’s yawning democratic deficit, Trump last week refused to activate additional sanctions against Putin and his oligarchs that had been agreed by Congress last year. He might just as well have donned a “Vote Vlad” campaign badge.

This latest sign of collusion came despite a recent Senate minority report that furiously decried the global threat posed by Putin’s Russia, and Trump’s “negligent” response.

“For years,” the report said, “Vladimir Putin’s government has engaged in a relentless assault to undermine democracy and the rule of law in Europe and the US. Mr Putin’s Kremlin employs an asymmetric arsenal that includes military invasions, cyber-attacks, disinformation, support for fringe political groups, and the weaponisation of energy resources, organised crime, and corruption.”

It added: “If the US fails to work with urgency to address this complex and growing threat, the regime ... will continue to develop and refine its arsenal to use on democracies around the world, including against US elections in 2018 ... Never before in American history has so clear a threat to national security been so clearly ignored by a US president.”

Trump’s blind eye is not unique. Theresa May lambasted Putin in November for meddling in other people’s elections and referendums. But neither she nor Boris Johnson has raised public objections to Putin stealing his own election. This silence contrasts sharply with oft-stated British concerns about upholding democracy in Africa and elsewhere.

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Europe’s leading lights, France and Germany, have not been any more outspoken, although the EU did jib at Navalny’s exclusion. The ban “casts a serious doubt on political pluralism in Russia”, it inoffensively declared.

And perish the thought that western governments might launch the same covert cyber and disinformation operations to influence Russia’s polls that Putin has used against theirs. There is certainly no sign of it. If they are trying, it isn’t working.

Why this shaming diffidence, even deference, towards Putin’s regime? Western ineffectiveness in sticking up for democracy in Moscow is matched by serial weakness over illegal Russian actions in Ukraine, the Balkans and Syria, where war crimes are committed daily under Putin’s imprimatur.

Perhaps western leaders fear instability, and financial and energy supply disruption, should Putin fall. Maybe an enfeebled, divided west has given up on post-Soviet, post-cold war democracy. In Trump’s case, maybe he admires the dictatorial strongman approach and wishes to emulate it. Apologists say we do not understand Russia and Putin. Yet the whole world understands a liar and a cheat.

• Simon Tisdall is a Guardian assistant editor and a columnist on foreign affairs