The row over the future of Russia's Black Sea Fleet in Crimea could become a flashpoint in the already strained relations between Kiev and Moscow, says the BBC's Rupert Wingfield-Hayes, as he goes aboard the Russian flag ship in Sevastopol.
There is a very serious question being posed to the West in the wake of the Georgia conflict.
The Moskva cruiser took part in last month's blockade of Georgian ports
In the aftermath of Russia's invasion, should Nato move ahead more rapidly with plans to bring both Georgia and Ukraine inside its protective fence?
The argument being made by many Western commentators and politicians is that it should. But sitting in Moscow one cannot help wondering whether those calling for Nato to expand further and faster really understand the complexity and potential dangers involved.
This week I went to Sevastopol on the Black Sea coast of Crimea, Ukraine.
Sevastopol has twice been besieged by invading European powers. Just down the road is Balaklava where the British Light Brigade famously charged to their deaths in 1854. Florence Nightingale set up her hospital nearby. In 1941, it was Hitler's turn to lay siege.
Sevastopol is one of the most delightful cities anywhere. Once-grand neo-classical buildings dot the limestone hills that surround one of the most lovely natural harbours in Europe.
You can immediately see why the Russians chose this spot to build their great naval city.
Today, what is left of Russia's mighty Black Sea Fleet still rides at anchor in the harbour below.
I was taken aboard the flag ship, a huge grey monster called the Moskva (Moscow), an 11,000-tonne missile cruiser built during the Cold War to take on America's aircraft carriers.
The Moskva is now more museum piece than threat to the US Navy. But it, and its sister ships, still have the potential to bring the West and Russia in to conflict once more.
On board with the Russian Black Sea Fleet
The problem is that, by a quirk of history, when the Soviet Union collapsed Sevastopol ended up in Ukraine. Russia has a lease on the naval base until 2017. Then Ukrainian President Victor Yushchenko says the navy must go.
But the Russians have no intention of leaving.
"We built this place more than 200 years ago," Rear Admiral Andrei Baranov, the current commander of Russia's Black Sea Fleet told me. "Its steeped in the history of the Russian Fleet."
If you climb up the slopes behind the naval base you can find some of that history in the thousands of graves of Russian sailors, from humble deck hands, to famous admirals.
We built this place more than 200 years ago. Its steeped in the history of the Russian Fleet
Rear Admiral Andrei Baranov head of Russia's Black Sea Fleet
In the naval church high on a hill overlooking the harbour, I met Father Igor.
With his long grey beard and flowing robes he was the very picture of a Russian Orthodox priest. But when it comes to Ukraine joining Nato he is every inch the Russian nationalist.
"The West is always trying to subdue Russia” he told me.
"Russia can remain patient for a long time, but then it will unleash its deadly punishing sword. Russia has already shown it can do it, in Georgia. The West shouldn't provoke it here."
Nato is seen by many Russians as being deeply antagonistic towards Russia. More than 90% of Sevastopol's population is Russian-speaking, and they are absolutely opposed to Ukraine joining the alliance.
'We choose Russia'
Sitting in a Sevastopol street cafe, my ears were suddenly assaulted by the sound of a mass of car horns.
More than 90% of Sevastopol's population speaks Russian
Then up the street came a long line of cars all hooting madly, with huge Russian flags sticking out of their windows.
Far from being annoyed by this spectacle many of the other car drivers joined in the frantic hooting.
The convoy was from a group called "we choose Russia".
"The Ukrainian nationalists in Kiev are trying to push us Russians out of here," said the group's leader, local MP Gennady Basov.
"If this continues, we'll have no choice but to defend ourselves with any means possible."
"Does that include taking up arms?" I ask him. "By whatever means," he repeats.
It sounds like an empty threat. But there is no doubt that Ukraine's Russian minority is as determined as Moscow to stop Nato's expansion further east.
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