A Russian annexation of Crimea is apparently underway, with thousands of Russian troops already in de facto possession. NATO does not have treaty obligations to defend Ukrainian territory and the Russian military has a very healthy military arsenal. Generally countries with nukes try not to go to war with other countries with nukes.
So that leaves the question of what the US and its European partners could do to penalize Russia for its actions.
One step could be to go after the assets of Ukrainian and Russian oligarchs close to the Kremlin, and the ill-gotten wealth of many of the members of President Vladimir Putin's inner circle. But if Britain has anything to say about it, any step in that direction would likely be highly discretionary.
The Guardian reported Monday that a photographer had snapped a photo of a document in the hands of an official entering the prime minister's offices. British officials are apparently so careless with government documents that freelance shooter Steve Back has made a career of this.
While the document isn't government policy – for all we know it could be a proposal that was shot down – it underlines just how far Britain, and probably many other EU states, would be willing to go to back up their high-minded rhetoric about "international norms." The short answer? Absent a major military escalation from Russia, not very.
Among the points in the photographed document was a recommendation that Britain should oppose trade sanctions against Russia, at least for the moment, and that "London's financial centre" should remain open to Russians.
There's a good reason for that. Tax revenue from financial services is worth about $105 billion a year - about 12 percent of UK tax revenue. Over the past decade, Russian and Ukrainian oligarchs, amongst other rich foreigners, have flooded London's banks and real estate market. Many of these rich and politically-connected businessmen made their fortunes from the natural resources grab that followed the collapse of the Soviet Union. One sign of that tide of cash was the $360 million purchase of Chelsea Football Club by Roman Abrahamovich, a Russian entrepreneur.
Targeting Russian assets in Britain could be costly – and disruptive. It would not only do damage to current investments but also send a message to other foreign billionaires that London isn't such a safe destination for their cash. And the current mantra seems to be "what's good for the City of London is what's good for Britain."
And it's not the only area where national economic concerns are likely to trump worries about Russia's invasion of Crimea.
Russia is the biggest gas supplier to Europe – about 25 percent of total consumption – and earns roughly $100 million a day (about $36 billion a year). While a loss of that revenue would hurt Russia, a loss of supply would hurt European nations. Energy has long been a powerful card in Vladimir Putin's back pocket should he chose to wield it. And winter isn't over yet in Europe.