Earlier this week, US authorities said they believe Russian forces have not managed to execute their apparent plan to quickly seize Ukraine's two largest cities, Kyiv and Kharkiv. The Pentagon believe this is because of "creative" resistance from Ukrainian troops.
"They have not achieved what we believe they intended to achieve by day four. So in many cases, they're behind schedule," the defence official said.
"We don't know if it's a failure in planning. We don't know if it's a failure in execution," they added.
While it is unclear when this might happen, experts speaking to the BBC have been examining potential ways the war could come to an end.
While some believe this is very unlikely, Professor Sir Lawrence Freedman, Emeritus Professor of War Studies at Kings College, London, says it is "now as likely that there will be regime change in Moscow as in Kyiv".
"Putin, who has isolated himself, in all senses of the word, risks now losing that aura of ruthless power that he has carefully cultivated," Prof Freedman writes.
"That aura meant that only the bravest of domestic opponents took him on and autocrats elsewhere embraced him as an exemplar to follow.
"What will matter most will be rumblings among the elite as they see the consequences of their leader's recklessness," he wrote.
"When we know more about how this war ends we will understand better how his regime ends."
Russia seizes Kyiv
Russia could up the ante on its military operations, leading to further attacks across Ukraine. This would go hand-in-hand with major cyber attacks across the country, along with shutting down energy supplies and communication networks.
Despite Ukraine's resistance, the capital falls within days. Ukraine President Volodymyr Zelensky is killed or flees into exile.
Putin declares victory and installs a pro-Russia puppet leader.
Given Ukraine's brave rebellion against the Russian invasion, the prospect of conflict breaking out again would be high, experts say.
The invasion could potentially evolve into a more prolonged war than Russian forces expected.
This fighting echoes Russia's long and brutal struggle in the 1990s to seize and largely destroy Grozny, the capital of Chechnya.
But, even if Russia achieves some presence in Ukraine cities, they may struggle to maintain control and eventually leave Ukraine – just as their predecessors left Afghanistan in 1989 after a decade fighting Islamist insurgents.
Putin could potentially seek power in more parts of Russia's former empire or declare the West's arms supplies to Ukraine as an act of aggression – which could "justify" his means to retaliate.
With the current unpredictability, a peace agreement could be a potential resolution.
Russian and Ukrainian officials had their first round of talks on the Ukrainian-Belarusian border. Despite bringing no results, Putin has, at least, accepted the possibility of a negotiated ceasefire.
"The guns are talking now, but the path of dialogue must always remain open," said UN Secretary General António Guterres.
President Macron of France has also spoken to President Putin on the phone. Diplomats say feelers are being stretched out to Moscow. One of the focal questions is whether the West can offer an "off-ramp", an American term to describe an exit off a highway. Diplomats say Putin must know what it would take for Western sanctions to lift, so a deal is at least possible.
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