Three children sit in the back of a police van, their faces pressed against the bars. 

They are still clutching homemade signs calling for peace. "No war," says one banner. "Russia plus Ukraine equals love," says another. Soon, the children are driven away into the freezing Moscow night. 

As the war in Ukraine enters its eighth day, the pressure on Vladimir Putin is mounting. Ukrainians are resisting. The West has accused him of war crimes. In Moscow, more Russians are protesting as economic sanctions make life harder for ordinary people. 

On Tuesday, American president Joe Biden warned the Russian leader "he has no idea what is coming". 

Now, people worldwide are asking: how much longer will Putin stay in power? For British writer Edward Lucas, a popular uprising is no longer unthinkable. 

"If the history of strongmen is any indication, it may be downhill for the Russian leader from here," adds one American journalist. 

After 22 years in power, could Vladimir Putin be overthrown by his own people like Egypt's Hosni Mubarak, put on trial for war crimes like Serbia's Slobodan Milosevic or even killed by an angry mob like Libya's Colonel Gaddafi? 

But others say this is very unlikely. Russians are used to hardship. People as young as 40 can remember hunger and empty supermarkets. 

And millions of Russians get their news from state-run television. Presenters accuse Ukrainian forces, not Russian forces, of war crimes. 

"When you try to reason with an average person in Russia, they might say something like: 'The TV is right and you're wrong'," writes one young Russian journalist. 

Meanwhile, critics of Putin are often jailed. Others are scared into silence.

One thing is clear: Putin's fate will change the course of history for the entire world. 

Yes: Conflicts once led to an outpouring of domestic support for Putin. This time, he has made a mistake. Hardship, oppression and the death of their soldiers will push Russians to fight for change. 

No: Putin rules Russia with an iron fist. Brutal crackdowns will prevent protests from growing. And not all Russians are against the invasion. 

Or... Change takes time. The costs of war will eventually take their toll, leaving Russia weaker and Putin in danger.

Sanctions - Economic measures designed to punish a country, for instance by excluding it from trade.