The disagreement between Russia and the west over the Conventional Armed Forces in Europe treaty is one of the most complex issues on the diplomatic agenda this autumn. Yet, for all the -complexity, what is at stake is the survival of a hugely important defence agreement, one which neither Moscow nor Washington can afford to see abandoned.
The CFE pact, signed in 1991 and amended in 1999, not only limits the number of tanks, artillery, military aircraft and helicopters deployed by Russia and Nato states, it also contains a raft of confidence-building measures involving, for example, mutual notification of overflights or the firing of -missiles.
"If you lose the CFE, the ability of European states to oversee military activity in other countries would disappear overnight," says Christopher Langton, senior fellow for conflict and defence diplomacy at London's International Institute for Strategic Studies. He believes there is good reason to hope Nato and Russia will settle their differences at a critical meeting in Madrid at the end of this month. "There will be an attempt to salvage the CFE because, despite all the rhetoric, there's a general desire to save what has been the only European agreement on security that binds the -Russians and all the Nato countries."
Why then, is tension over the treaty now so high? Technically, the disagreement between Russia and Nato lies in two crucial areas. First, Moscow wants the three Baltic states - Estonia, Latvia and Lithuania - to be covered by the CFE provisions. These three states were still part of the Soviet Union when the CFE was agreed in 1991 but are now part of Nato.
"They are now in a legal limbo and they constitute a northern flank area for Russia in which the military build-up has worsened in recent times," says a senior Russian diplomat.
Second, Nato has its own demands. It says it will not ratify an amended version of the CFE unless Russia abides by what it believes is a commitment from Moscow to withdraw troops from two former Soviet republics, Moldova and Georgia. One of Nato's concerns may be that, if Russian troops remain in those two states, this will slow down any attempt to make both countries Nato members.
These technical differences are only part of the story. The situation has been exacerbated because the US and Russia are taking a tough stance on CFE to improve their bargaining position on other diplomatic issues.
Tomas Valasek, a defence expert at the Centre for European Reform in London, says: "Russia . . . has calculated that, unless it keeps up the pressure on CFE, the US won't move on its plans to deploy a ballistic missile defence system."
With little more than a month to go before Russia's deadline to quit the treaty expires, will all sides recognise the CFE's underlying value? As Mr Langton puts it: "This treaty was formed on the basis of pragmatism. It is being hijacked by politics by the two biggest players on the world stage."
