Russian President Vladimir Putin has yet to publicly comment on a lightning rout of his forces in north-eastern Ukraine, but is under pressure from nationalists at home to regain the initiative.
Since coming to power in 1999, militants in Chechnya and the wider North Caucasus region are among the toughest armed foes Putin has faced. In that instance, he chose to escalate with more force.
These are some of his main options in Ukraine:
Stabilize, regroup, attack
Russian and Western military analysts agree that -- from Moscow's point of view -- Russian forces need to urgently stabilize the frontline, halt Ukraine's advance, regroup and, if they can, launch their own counter offensive. There are however doubts in the West about whether Russia has the ground forces or sufficient equipment, given how many casualties it has taken and how much hardware has been abandoned or destroyed during what Russia calls its “special military operation” to destroy the Ukrainian army.
“There is no manpower,” Konrad Muzyka, director of Poland's Rochan Consulting, said after Russia's setback in the north-east.
“Volunteer battalions are under strength, and the recruitment campaign is not delivering what was expected. And I think it will only get worse as fewer men will now want to join. If Moscow wants to add men, it needs to conduct a mobilization.”
Russian efforts to increase the number of troops it can deploy include the formation of a new 3rd Army Corps, Chechen leader Ramzan Kadyrov marshalling new forces, and Putin last month signing a decree to increase the size of Russia's armed forces.
Putin will need to decide whether to agree to demands from nationalist critics that he sack or reshuffle the military's top brass, including Defense Minister Sergei Shoigu, a close ally. Putin has traditionally not given in to immediate pressure to fire subordinates, but has sometimes parted company with them at a later date.
Mobilizing Russia's reserves, who number around 2 million men with military service within the past five years, is doable but it takes times to train and deploy people.
The Kremlin said on Tuesday there was no discussion of a nationwide mobilization “at the moment.”
Such a move would be popular with nationalists, but less so with some Russian men in urban centers who, anecdotal evidence suggests, are less keen on joining the fight.
It would mean recalibrating official messaging on Ukraine and moving away from describing it as “a special military operation” with limited goals to an open-ended war.
That in turn would force the authorities to abandon their policy of trying to ensure that the lives of most Russians go on as they did before Feb. 24 when Putin invaded Ukraine.
Putting Russia on a full wartime footing would come with domestic political risks too, notably the risk of a public backlash against a forced draft.
It would also constitute an admission that Russia is engaged in a full-scale war against a fellow Slav country - and that the war is going badly for Moscow.
Andrey Kortunov, head of RIAC, a think tank close to the Russian foreign ministry, has said he believes the authorities are reluctant on mobilization.
“In big cities many people do not want to go and fight and mobilization is not likely to be popular,” said Kortunov.
“Secondly I think it is arguably in Putin's interests to present the whole thing as a limited operation. The state would like to preserve as much as possible as it was before without making any radical changes.”
Tony Brenton, a former British ambassador to Russia, has said it would take months before a mobilization would have any effect on Russia's fighting strength in any case.
Bet on ‘general winter’
Two Russian sources familiar with Kremlin thinking told Reuters last month that Putin is hoping that sky-rocketing energy prices and possible shortages this winter will persuade Europe to strong arm Ukraine into a truce -- on Russia's terms.
Some European diplomats believe that Ukraine's recent battlefield success has undermined the urge of some Europeans to push Kyiv to make concessions however, while countries like Germany appear to have grown tougher on Moscow in recent weeks and more determined to ride out winter energy problems.
The European Union has banned Russian coal and approved a partial ban on Russian crude oil imports. Russia in turn has sharply cut gas exports to Europe and made clear it could ban all energy exports, a lever Putin has yet to pull.
Expand missile targeting
After its setback in north-east Ukraine, Russia struck Ukrainian power infrastructure with missiles. That caused temporary blackouts in the Kharkiv and adjacent Poltava and Sumy regions. Water supplies and mobile networks were also affected.
The move was cheered by some Russian nationalists who would like to see Moscow use cruise missiles to cripple Ukrainian infrastructure on a more permanent basis, a move certain to attract international condemnation.
The same nationalists have also long called for Moscow to strike what they call “decision-making” centers in Kyiv and elsewhere, something that it is unlikely could be achieved without significant collateral damage.
End or downgrade grain deal
Putin has complained that a UN and Turkey-brokered deal that allows Ukraine to export grain and other foodstuffs via the Black Sea is unfair to poorer countries and Russia.
Putin is due to holds talks this week with Turkish leader Tayyip Erdogan to discuss revising the deal, which provides Ukraine with much needed budget revenues. If Putin wants to immediately hurt Ukraine he could suspend or cancel the pact or refuse to renew it when it expires in November. The West and poorer countries in Africa and the Middle East would accuse him of worsening global food shortages; he would blame Ukraine.
The Kremlin says it will dictate to Kyiv the terms of any peace deal when the time comes, while Ukrainian President Volodymyr Zelenskyy has said he will use force to liberate his country.
Zelenskyy has said that includes Crimea, which Russia annexed in 2014. Moscow has repeatedly said that Crimea's status is settled forever.
Conceding captured territory in eastern Ukraine in the Russian-backed self-proclaimed Donetsk People's Republic or Luhansk People's Republic also looks politically impossible for Moscow as it has formally recognized them.
Fully “liberating” the two self-proclaimed statelets from Ukrainian forces was one of the main reasons given for the “special military operation” in the first place.
Handing back captured territory in southern Ukraine where Russia partially controls three regions looks like a hard domestic sell too.
The southern Kherson region is directly north of annexed Crimea and the location of a canal which supplies the Black Sea peninsula with most of its water.
Along with the neighboring Zaporizhzhia region, Kherson also gives Russia a land corridor through which it can supply Crimea, something Moscow has touted as a major prize.
Russian government officials have dismissed Western suggestions that Moscow would use tactical nuclear weapons in Ukraine, but it remains a worry for some in the West.
Apart from inflicting mass casualties, such a move could start a dangerous escalatory spiral and formally draw Western countries into a direct war with Russia.
Russia's nuclear doctrine allows for the use of nuclear weapons if they - or other types of weapons of mass destruction - are used against it, or if the Russian state faces an existential threat from conventional weapons.
Putin, in a quasi-autobiography in 2000, recalled cornering a rat in a corner with a stick when growing up in a dilapidated apartment building in then Leningrad and being surprised when the cornered animal threw itself at him and turned the tables.
Brenton, the former British ambassador to Russia, has warned that a cornered Putin could go nuclear if he faced a humiliating defeat with no face-saving off-ramp.
“If the choice for Russia is fighting a losing war, and losing badly and Putin falling, or some kind of nuclear demonstration, I wouldn't bet that they wouldn't go for the nuclear demonstration,” said Brenton.
Retired US general Ben Hodges, former commander of US Army forces in Europe, agrees it's a risk but has said he thinks it unlikely.
“There is no real battlefield advantage to be gained, it would be impossible for (the) US to stay out/not respond, and I don't think Putin or his closest advisers are suicidal,” said Hodges.