by system failure
The government coalition in Greece has lost more power in recent euro elections and literally struggling hard to stay in power. The middle class in Greece has been hit directly by the cruel neoliberal measures imposed by the Troika lenders and more people express their anger against government policies.
The latest governmental "achievement" was to follow immediately Western sanctions against Russia, something that triggered Russia's response to block many Greek products from the Russian market.
Under such catastrophic scenery for the economy, many small-medium businesses in Greece are struggling to survive and the Russian blockade was a major hit for them. Although the mainstream media refer to these problems, the statements of market representatives in all central news, asking from the government to impose pressure to the EU to give compensations and find new markets, are only cover the real picture of a society which is ready to explode.
At the same time, NATO allies, like Turkey, seem to ignore the US demands, and take advantage of Russia's blockade to Greek products, to promote their products to Russian market. Germany seems to follow its own policy, especially concerning energy supply, while even some US companies seem to defy Washington's willing to isolate Russia: http://rt.com/business/179200-exxonmobil-rosneft-arctic-drilling/
In such an economic disaster scenery, Greece had all the excuse not to follow sanctions against Russia, but the government chosen to align with Washington's will. Greek government officials claim that it's a matter of national security to align with the allies' decisions, hoping, probably, for some rewards on national matters.
Apparently, they forgot the stance of the US against their puppet junta regime in Greece and the role of Henry Kissinger on the Turkish invasion in Cyprus back in 1974: http://failedevolution.blogspot.gr/2014/07/20-july-2014-40-years-from-turkish.html
Current Greek government has a constant policy line: Follow the orders of Troika and NATO without the slightest decline, without dare to examine alternatives closer to the interests of the country. That's because under the mask of patriotism, they hide their neoliberal beliefs and their willing to lead Greece into the new era of global feudalism, whose designers found the most faithful puppets to serve their plans.