The push from the south will come from the Black Sea Fleet of Russia. This currently consists of some 25,000 men and associated weaponry. This fleet resides in Crimean Sevastopol, as it has for the past 200 years.
The Russians know this trap works well. It was last used in Georgia in 2008 when South Ossetia, a region with a population which was strongly pro-Russian, sought to increase its autonomy. When the Georgian authorities attempted to reclaim this area, the Russians directed their military forces over the border under the guise of humanitarian intervention. For the price of about 1000 lives and 200,000 refugees, 20 per cent of Georgia was lost - and never recovered - over five days of fighting.
The conflict was not condemned by the Security Council because of the Russian veto. The West, despite large amounts of rhetoric and handwringing, did not intervene.
If Russia decides to invade Ukraine, the West will not intervene this time either. This is despite the fact that the death toll would probably be much higher. The higher death toll will be because the country, which is geographically bigger than France and holds nearly 45 million people, is quite well armed.
Although the Ukrainians voluntarily gave up their nuclear weapons in the 1990s, they retain a formidable military force. On the large assumption the Ukrainian military all shoot in the same direction - and not at each other - they may prove a much stronger opponent than the Georgians.
However, apart from firing some heavy statements, there will be no military assistance from the West.
There is no military alliance obliging the West to intervene. The Ukraine is not part of Nato. Nor is the Ukraine part of the traditional Western European family.
More than that, the West needs to work with Russia on other matters such as the crisis in Syria and the dismantling of the nuclear programme of Iran.
Vladimir Putin will be calculating this very complicated game at the moment. The Ukrainian crisis will be his paramount concern. He already feels betrayed by what he saw as the fraternal ally of Russia moving away. This is especially so since he was near to roping them into a closer economic and military relationship.
Putin is also aware that this this type of civil discord could spread through the pro-Russian region and into the Russian heartland itself. It is no coincidence that hundreds of opponents to Putin have recently been incarcerated. He will also be calculating his weight as a national, regional and global leader. He knows the perception to the outside world will be bad as it echoes the moves of Hitler in the late 1930s. If Putin is smart enough he will realise there is a way out of this where everyone can get something they need, without bloodshed. This would involve the use of robust democratic debate in the Ukraine over a very difficult proposal. That proposal would be granting strong autonomy, or independence, to the Crimea in exchange for a large sum of money and energy security. The Ukraine is in a financially poor position. It already needs US$30 billion ($36 billion) just to survive for the next two years. It is also heavily dependent on foreign energy sources.
Besides the obvious rubble, a war will make the economic and social development of this nation much more difficult in the coming decades. This is a horrible proposal, but there may be a deal to be made. The Ukrainians can ask themselves whether the ownership of the Crimea should change again, as it did in the 20th century, and if so, what the cost of this transfer would be? Although unpalatable, and potentially a type of appeasement, this equation is better than the alternative.
If war breaks out the Russians will be confident in their justifications and the Ukrainians will be forced to fight alone. It could be very bloody and the outcome is near certain. A deal could avoid the bloodshed, escape their economic turmoil, bypass the difficulties of trying to hold a population that does not want to be part of their nation and hopefully get the Western-leaning part of the nation a clean start.
This clean start could allow them to buy the time they need to fully integrate with the West. Or, they can spring the trap.
Alexander Gillespie is a law professor at Waikato University and author of The Causes of War, (2013 Oxford).
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