There’s no sugar coating it – it’s not been a good week for Russian President Vladimir Putin.

While the Kremlin has insisted what it’s called a “special military operation” is right on plan, it’s doubtful that plan included Ukraine retaking 8000 sqkm of occupied land including a major city and a vital transport hub in a just a matter of days.

Now rumblings in Moscow suggest Putin’s days could be numbered.

But careful what you wish for because some of the people that could jump into the top job might make Putin look almost reasonable by comparison.

“If the hardliners get in … they’ll want to send a message in line with Russian doctrine of ‘Udar’, which means massive shock in Russian. You would shock your enemy into surrender and you win,” Russian military expert Dr Rod Thornton of Kings College London was reported as saying in The Sun.

“I do fear the use of tactical nuclear weapons to send a message from the Russian military that they’re serious about Ukraine.”

Putin has years left to reign – unless he’s pushed

Theoretically, 69-year-old Putin could stay in power for another decade or more. That’s in addition to the mere 16 years he’s already been in power.

A change to the constitution in 2021, engineered by Putin, means he could still be president in 2036.

But he will have to decide whether he stands for another six-year term relatively soon with this current stint ending in 2024. And that means now is the time for wannabe presidents to get into gear.

“Putin himself demonstrates no intention to step down, but looks increasingly relegated to the past,” says Andrey Pertsev who writes for US think tank the Carnegie Endowment for International Peace.

“The elites and potential successors are watching his every military move, but they can already see that he has no place in their post-war vision of the future.”

Putin’s ‘ship is sinking’

Commentator and author CJ Farrington put it even more succinctly in The Spectator.

“The ship is beginning to sink, and the rats are beginning to swim.”

In the last week some Russian politicians, bravely and possibly foolhardily, have begun to question Putin’s strategy in Ukraine following Kyiv’s advances.

Quietly, in the shadows, wrote Mr Pertsev, there is now a battle between those who wished the war never happened and those determined to see Ukraine crushed.

“The war has set in motion a public race of the successors,” he wrote in August, before the Ukraine advance.

The strong and silent candidates

Some who hope to take over from Putin are – possibly deliberately – almost silent on the invasion.

The explanation, Mr Pertsev said, was their belief that the war was a “temporary affair” and at some point Russia will look to restore relations with the West and possibly Ukraine.

“When that time comes, those who haven’t insulted ‘hostile countries’ or directly participated in the military campaign will be better placed to go about that.”

In this group can be put Prime Minister Mikhail Mishustin.

He used to head the tax office as is seen as one of Moscow’s most effective apparatchiks who actually makes government run better for the people.

Despite his reluctance to make bellicose statements in support of the war his still remains at the very heart of government.

Another possible candidate keeping his thoughts on Ukraine to himself is Moscow mayor Sergey Sobyanin, who is well liked by Russians and has a sizeable power base.

Security expert Mark Galeotti told Al Jazeera this month that should Putin go, the best anyone can hope for is a “pragmatic kleptocrat” who tries to end the war and get Russia out of the global bad books.

“Men like Mishustin or Sobyanin might fit that mould, but that’s not to say they are ever necessarily likely to rise to power.”

The hate filled hopefuls

But it’s also just as likely that a so-called “hawk,” filled with rage just like Putin could come to power.

One of those is deputy chairman of the Security Council of Russia and former President Dmitry Medvedev.

He led Russia from 2008-2012, a period where he was seen as a reformer – but those days are long gone.

During the conflict he has been one of the most vocal theatrically lashing out at Kyiv.

He hoped, for instance Ukraine “disappears from the map”.

“They are bastards and degenerates. They want us, Russia, to die. And while I’m still alive, I will do everything to make them disappear.”

Which doesn’t bode well for Ukraine if he retakes the wheel.

A common name thought to be on the list of succession was defence Minister Sergei Shoigu. However, the campaign in Ukraine has met so many setbacks that it seems almost certain he is out of favour.

Alexander Bortnikov is one of Putin’s “Siloviki” or inner sanctum of advisers and enforcers. A former KGB man, like Putin, he is a director of its successor the Federal Security Service (FSB).

Another name is Alexei Dyumin, a former bodyguard of Putin’s that he liked so much he promoted into political posts. Possibly because Dyumin once saved Putin from a bear attack.

In 2014 he was key in the annexation of Crimea from Ukraine and so, for supporters of the war, he has impeccable credentials.

The ruthless extremist

And then there’s Nikolai Patrushev, one of Putin’s closest Siloviki and also a KGB alumnus.

The secretary of the powerful Russian Security Council, he’s so ruthless he’s been called “the hawk’s hawk”. During recent years, as Putin’s circle has tightened, Patrushev’s extreme views and hatred of the West have influenced the president.

“Both Putin and Patrushev deplore the end of the Soviet Union, and both share a deep distrust of the West that is fuelled by nonsensical conspiracy theories,” wrote Sussane Strenthal, a lecturer at Texas State University on website The Conversation.

“Patrushev has emerged as one of the leading voices in Putin’s inner circle who wants to wage a merciless war in Ukraine, with the ultimate objective of capturing Kyiv.”

Ex British secret service chief Sir Richard Dearlove said he was in pole position.

“I would go as far as to say almost for certain, it would be Patrushev at the moment.” he was reported as saying in Newsweek.

Although Sir Dearlove added that long term, Patrushev might fall out of favour.

If he were to succeed Putin there is a real possibility he would throw even more resources at pummelling Ukraine. That could include conscription of ordinary Russians to fight on the front line and the merciless, bloodthirsty destruction of Ukrainian cities.

“The two strategies — loud gestures and resounding silence — reflect the different approaches and assumptions of those who use them,” said Mr Pertsev in Carnegie Politika.

“The hawks operate on the basis that the successor will be chosen by Putin, so they mimic his behaviour in their attempts to win his favour.

“Those remaining silent are counting on a different succession scenario.”

Putin has such as strong grip on power that his role does not – yet – seem threatened. But he has not covered himself with glory in Ukraine and that means his once unshakeable position at the top of the Russian elite might just be wobbling.

If he does topple, the worry is what comes next. It might not be peace.