Geography. This is a strategically important region. The country's modern constitution dates from July 1995 though it became independent of the former Soviet Union in 1991. There is a long standing disagreement between Armenia and Turkey regarding the horrific events during World War I when possibly well in excess of one million Armenians were killed - see here for more detail.
In October 2009, Turkey and Armenia signed a historic accord normalising relations between them after a century of hostility. However, Armenia wants Turkey to recognise the killings as an act of genocide but successive Turkish governments have refused to do so. See Armenia, Turkey sign historic agreement.
A vote in a committee of the United States legislature has called upon President Obama to classify the killings as genocide and, in consequence, Turkey withdrew its Ambassador to the U.S. - see The Times 5th March 2010. Ankara accepts that many thousands of Christian Armenians living in what was then eastern Anatolia died in blood-letting by Muslim Ottoman troops in 1915. It rejects the term “genocide” and says that the 1.5 million figure for the final death toll is exaggerated. Experts, including some of Turkey’s own most respected historians, disagree. Many governments, including the US and the UK, have refused to use the term genocide in connection with those events.
An analysis of the situation is the opinion of Geoffrey Robertson QC which was published in 2009. The learned author concludes that the treatment of the Armenians in 1915 answers to the description of genocide. See also Armenian Embassy London.
There is little doubt that what is now referred to as genocide existed as an international crime prior to the Genocide Convention of 1948 but it was ill-defined and tended to be classified under the more general heading of "crimes against humanity". A Resolution of the UN General Assembly in 1946 described genocide as a denial of the right of existence of entire human groups and went on to affirm that it was a crime under international law. However, prior to the 1948 convention, the crime was not well-defined though events such as the extermination of Jews was an obvious example. It required the 1948 Convention to provide a definition and to impose obligations on States to criminalise genocide through their national law and to co-operate judicially so as to suppress the crime. According to the Italian jurist Antonio Cassese (International Criminal Law 2nd Edition at p.127) - "Genocide acquired autonomous significance as a specific crime in 1948, when the UN GA adopted the Genocide Convention."
In recent years various International Tribunals have sought to interpret the Convention and to offer judicial rulings on the various elements of the crime. Cases have arisen in the International Criminal Tribunal for Former Yugoslavia and the International Criminal Tribunal for Rwanda.
It is reported that The White House has now moved to block the Armenian Genocide Bill which is going throught the US Congress - see here.
The vote in the US Congress is unlikely to assist the process of reconciliation between Armenia and Turkey and probably the involvement of other nations, other than maybe as honest brokers, is also unlikely to be helpful. It would seem desirable in the longer-term interests of both Turkey and Armenia that some form of resolution is achieved but it is unclear at the present time how, if at all, a satisfactory resolution will be brought about..
In English Law, the crime of genocide is now to be found in the International Criminal Court Act 2001.
Addendum Monday 8th March: Norman Stone (Professor Emeritus of Modern History at Oxford) argued in The Times that the horrific events of 1915 ought not to be classified as genocide and he points out that the Turks actually put 1600 men on trial and executed a governor. He sees the US Resolution as counterproductice and likely to encourage Turkey to turn away from the West and look toward China who, he says, are "quite active" in Ankara.
See also Denial of Armenian Genocide (Wikipedia).