Can somebody (UN, EU), anybody (OSCE, Switzerland), still mediate in the most dangerous European crisis since the big change of 1990?

The gravity of the crisis triggered by Putin's reckless gamble to get away with a forced but so far bloodless annexation of the Crimea is sinking in with the referendum's preordained success this past weekend. The West, including the US, has ruled out military action. But it will have to react more strongly than so far against this flagrant violation of all international norms (UN Charter, 'Helsinki', international law in general) and treaties (Declaration of Alma Ata, December 1991; Budapest Memorandum 1994; bilateral treaty between Russia and the Ukraine of 1997).

The US has taken the lead in a gradual stiffening of sanctions. Washington will go from the already signaled restrictions against a small circle of Putin's advisers to denial of international movement and blocking of assets abroad of a much larger part of the Russian economy and its exponents. First reactions based on market expectations seem to indicate that such measures would be powerfully felt.

 There are number of reasons why Washington has no choice but to act. Inaction would greatly reinforce the 'Weak Obama' chorus, however unjustified the sobriquet might be. Furthermore, as Gideon Rachman pointed out in the FT, China, Iran and Syria's Assad are all watching intently whether Washington will let Putin get away with murder.

Also, the US, as top dog of NATO, cannot tolerate Russian behaviour which makes the organisation's most exposed members in eastern and northern Europe uneasy. Hence the (so far modest) show of political and military strength at NATO's borders with the Russian sphere of influence.

But with military action ruled out, mediation, arrived at by a mix of sanctions and diplomacy, appears the only way out.

However, mediation presupposes two sides willing to move. Moscow has yet to give an inch. When the Russian MFA, early in the crisis, signaled possible agreement with a high-level contact group, the slack was quickly cut by the Kremlin and Foreign Minister Lavrov had to 'do a Gromyko'. His 'nyets' might be delivered with more elegance and superficial bonhomie than his Soviet predecessor, but they are just as categorical, indicating that Moscow's decisions continue to be made in one place and one place only.

But let's say, for argument's sake, that indications point to a real possibility for a diplomatic way out. Who would mediate? Obviously the UN comes to mind. But even if Russia was willing to deal, it would probably not do it through the UN. Not even Putin's authoritarian soul mates, be they in East Asia or elsewhere, would follow Russia on this path, and the dangers of walking it alone are too evident. 

The EU then? Brussels is of course party in this dispute. As we remember, at the origin of the present crisis was an about-face by then President Yanukovich, who chose to not sign a general agreement with the EU. 

The EU has so far shown quite a bit of restraint with regard to wielding the embargo weapon. This was due to London and Berlin. As has been reported at length, Cameron's cold feet regarding the effect of real sanctions on the City of London have so far outweighed the pull of the special Atlantic relationship. Yet this will likely change fast if Russia remains intransigent.

The key to the EU's position lies in Berlin. Germany is by far the largest EU user of Russian energy and would have much to lose in the event of a relapse into European cold war. At the same time, Angela Merkel, given her youthful experience, is probably the least likely German chancellor since the Second World War to buckle under authoritarian bullying. As was widely reported last week, she has come to the conclusion that 'Putin lives in different world' from the West.

Thus the EU, for once not only under economic but also political leadership from Germany, might well be the most active party cajoling all sides towards compromise. Once Western sanctions on Russia begin to bite, the outlines of a solution might be that Brussels will on the one hand offer Kiev help (but not membership), and on the other allow Putin to save face through economic incentives and an end to sanctions.

But if not the UN or EU, perhaps the OSCE? Problem here is that the Russian land grab in the Ukraine violates its basic principles. The Helsinki Charter limits the case for self-determination for part of an existing member country strictly to a non-violent, all-consensual path (eg. the 1993 dissolution of Czechoslovakia into two independent republics). The organisation has the means and the experience to supervise a process of changing national frontiers but cannot do so in a case of clear-cut aggression such as we witnessed in the Crimea.

Moreover, especially since Putin has reigned in Moscow, the Russian have not hidden their low esteem for the whole Helsinki process which they see, not without reason, as one of the main drivers of the implosion of the USSR and the liberation of eastern Europe. Just as UN representatives were muscled out of the Crimea, a first group of unarmed OSCE observers was not even allowed entry into the peninsula. The organisation has military observers in other parts of the eastern and southern Ukraine, sent on request by the provisional government to observe military movements there and just across the border with Russia.

At best, the OSCE could help once some sort of a compromise has been found. What it cannot do without creating a catastrophic precedent for the European construction since 1990 is compromise its principles by occupying a position between the two opponents. The OSCE Chairman for 2014, Swiss President Didier Burkhalter, has already designated the referendum as illegal.

Some have called for 'neutral mediation' in a supposed throwback to the Cold War, when there were four officially neutral countries in Western Europe (Finland, Sweden, Austria and Switzerland). However, leading Finnish politicians and historians have already clearly indicated why the historical, geographical and political realities are too different to allow for the 'Finlandisation' of the Ukraine.

The idea of profiting from the coincidence of the Swiss OSCE chairmanship to employ 'neutral mediation' is even more of a non-starter. To begin with, neutrality never meant ideological equidistance. Switzerland cannot and would not want to be seen in any kind of moral in-between position with regard to Russia and the Ukraine. Furthermore, Russia is these days very much part of the world's economy. So is Switzerland, especially its financial market. It is inconceivable that the Swiss, and especially Swiss banks, would be allowed to somehow sit out embargo measures against Russian assets solely in the interest of mediation activities by Bern.

Perhaps the solution could be found in a 'G2' of Washington and Moscow. This is not the same G2 so many analysts had on their strategic maps only a short while ago. But all those many countries welcoming an Asian pivot by Washington will have to wait longer. A new, unexpected and major front has just opened for the evidently still indispensable power, America.