There are 100,000 Russian soldiers on the border with Ukraine. On the other side, desperate civilians are training as volunteers. Any day, they could have to defend their country in the event of an attack. This is Europe's next war zone.

NATO countries have promised aid to Ukraine. But they are divided about what it will be. Many think that Russia is bluffing - that it does not truly want to take on the USA in a war. 

But others are less sure. The Russian army is modern and well-trained. And it is on familiar terrain. It could inflict serious damage on any American force.

Western powers would prefer a diplomatic solution to the crisis. But to get that, they need to work out what Vladimir Putin wants.

Putin is unlike most Western leaders. He has built up a reputation as a scrappy street fighter. He is prepared to fight harder than his opponents. 

But he is also a cold, calculating, ruthless thinker. He spent his early years in the KGB. He loves ice hockey: the perfect combination of grace and violence. And he is known for his skill in judo and sambo. Both are martial arts that teach their students to watch for an opponent's weaknesses and use their own strength against them.

Putin has often used his skills against Russia's international rivals. He tests how they respond to his actions so that he can predict their next move. And he calls their bluff when he needs to. 

Very few Western leaders understand what motivates Putin. As a result, they can be surprised by his decisions.

But some believe what makes Putin truly dangerous is the fact that he does not understand Western leaders. When his knowledge is incomplete he fills the gaps with plots and conspiracies.

Spreading democracy has been key to American foreign policy for years. It is not intended to be a threat to Russia.

But Putin sees it as a Western plot. So when Russia's neighbours have democratised their governments and applied to join NATO, he has responded aggressively.

Whether or not war breaks out in the coming days, the West and Putin will keep finding themselves clashing unless they can come to a better understanding of each other.

Yes: Putin is not a foolish thug. He is a thoughtful man with a keen strategic mind. He has worked with the West before and knows its weaknesses. We should not write him off.

No: We know all we need to know about Putin. When he feels threatened, he resorts to violence. He does not care that an invasion of Ukraine would cost thousands of lives. The only tactics he knows are bullying and brinkmanship. Understanding his traits will help us control the situation.

Or... We should use our understanding of Putin to come to a peaceful conclusion. We know that he might lash out when threatened. But we also know that as a strategic man, he will understand the risks in starting a war and taking on huge world powers. This is the key to a solution.