His army has made three humiliating retreats in Ukraine in the past year and nearly 200,000 of his men have been killed or wounded according to US officials, but Russia's defence minister is still in a job thanks to president Vladimir Putin.
The Russian leader has various reasons for keeping Sergei Shoigu, 67, in post, according to Western officials, veteran Kremlin watchers and former Western military commanders: he's ultra loyal, helped Putin become president, and decision-making on Ukraine is not his preserve alone.
Loyalty always trumps competence in the Putin inner circle.
"Loyalty always trumps competence in the Putin inner circle," said Andrew Weiss, a Putin specialist at the Carnegie Endowment think-tank who held various policy roles on the US National Security Council and has written a book about Putin.
Putin has admitted publicly he finds it difficult to fire people and usually handles such matters personally, said Mr Weiss.
"Several people in senior positions, all of whose job performance leaves a lot to be desired, including Shoigu, benefit from this under-appreciated sentimental side of (Putin's) personality," he said.
The Russian Defence Ministry did not respond to a request for comment on Shoigu or its own performance in Ukraine where its forces are pushing hard to try to capture the city of Bakhmut and the town of Vuhledar in the east.
Shoigu, a gruff hardliner who trained as a civil engineer, has held top jobs in Russia's power structures continuously since the collapse of the Soviet Union in 1991, and served as emergencies minister under late president Boris Yeltsin.
Appointed defence minister in 2012, he is part of Putin's inner circle and has enjoyed hunting and fishing holidays with him in his native Siberia.
Tatiana Stanovaya, founder of the R.Politik analysis firm and a well-connected Kremlin watcher, said Putin preferred to work with people he knew well despite flaws they might have.
"For him, it's psychologically easier," she said, pointing to a profile of Shoigu in which she had highlighted that Shoigu in 1999 was one of the leaders of a political party that helped propel Putin to the presidency.
"Ever since, Putin has been in some sense indebted to Shoigu," Ms Stanovaya said in the profile for online outlet Riddle.
"The latter has been guaranteed a comfortable place in Russian politics - provided that he did not commit any serious blunders."
A source close to the Russian authorities who declined to be named because they were not authorised to speak to the media cited an old Russian saying to provide another reason why they thought it was unlikely Shoigu would be replaced anytime soon.
"You don't change horses mid-stream," they said, a reference to the need to ensure continuity in turbulent times. The Russian army has been learning from its mistakes and successfully adapting, the source said.
A senior Nato diplomat and a senior EU official said they regarded Putin and his generals as the main decision-makers on Ukraine anyway, rather than Shoigu.
Ms Stanovaya said Shoigu was focused on managing his vast ministry and its ties with the defence industry, meaning that responsibility for the Ukraine campaign was shared.
"Putin himself works (on Ukraine) with the generals, not just with one or two figures, and sometimes gets involved in the (battlefield) situation at a lower level too," she said.
Chief of the general staff Valery Gerasimov was last month appointed to run the war in Ukraine, with Sergei Surovikin, nicknamed "General Armageddon" by the Russian media, demoted to deputy commander of the operation.
Both men, unlike Shoigu, are career military officers. Sergei Markov, a former Kremlin adviser, said Surovikin was still heavily involved in Ukraine despite his demotion.
'String of defeats'
The Kremlin says it will achieve its goals in Ukraine in what it calls a "special military operation" and has dismissed Western estimates of its casualties as exaggerated. Russian forces still control around one-fifth of Ukraine and are suspected by Kyiv of gearing up for a big new offensive.
However, Russia's invasion is widely regarded to have shone an unflattering light on Moscow's military, which was beaten back from Kyiv, routed in northeast Ukraine, then forced to surrender the southern city of Kherson.
Yevgeny Prigozhin, founder of Russian mercenary group Wagner, has been one of Shoigu's most fiery critics, claiming that his own men, who have spearheaded several assaults in eastern Ukraine, are far more effective than the regular army.
Prigozhin has avoided personal attacks in recent weeks since apparently being asked to desist by the Kremlin; he earlier called the army's top brass "bastards" who should be sent barefoot to the front with machine guns.
Igor Girkin, a former Federal Security Service officer who helped launch the conflict in 2014 with a Moscow-backed separatist uprising and is under US sanctions, has repeatedly questioned Shoigu's competence too.
"I would really like to know when this ... slacker will finally be court martialled for the way he 'prepared our army for war'," Girkin wrote in his blog this month.
Ben Hodges, former commander of US Army forces in Europe, told Reuters he had thought both Shoigu and Gerasimov would be fired as they had not delivered armed forces "capable of carrying out the task they were given ... There's no escaping the poor performance of the Russian military".
Hodges and Rupert Jones, a retired major-general who served as the Assistant Chief of Britain's General Staff, pointed to what they said were the Russian army's poor initial planning, strategy, tactics, logistics, equipment, as well as a botched mobilisation drive and corruption problems.
It was "inconceivable", said Mr Jones, that a Western defence minister could have kept his job in such circumstances.
"He would have been sacked, he would have fallen on his sword because he would have seen his own failings, or the media or public would have been looking for blood," he said.
Despite Moscow's mistakes in Ukraine, Jack Watling, a senior research fellow at the London-based RUSI think-tank, said Shoigu had "massively increased" the military's capabilities and overseen complex yet successful operations before Ukraine.
"So it wasn’t all bluster," said Mr Watling.
But he said Shoigu had oversold the army's new strength.
"The problem is that Putin and (Chief of the General Staff) Gerasimov seem to have believed those myths as well and had a very inflated sense of their own capabilities."
