The reductions in both countries' strategic arsenals to the 1,550 deployed strategic warheads agreed four years ago do appear to be going ahead. But Putin has made clear that he has little interest in a more ambitious follow-on treaty that would have addressed the issue of tactical nuclear weapons in Europe.
The US has an estimated 150-200 such weapons: B61 gravity bombs, based in Netherlands, Belgium, Germany, Italy and Turkey. Russia has 2,000 warheads for short-range missiles and artillery shells. Putin has cut off discussion on the subject and even raised the possibility of deploying nuclear-capable Iskander missiles in Kaliningrad, a Russian enclave between Poland and Lithuania.
Putin wants to link negotiations on tactical nuclear weapons to the issue of US missile defence sites in Europe. Washington insists that the system under construction is only intended to defend against a putative Iranian and North Korean threat and the US has cancelled the last and most capable phase of the project, but the Russian leader has shown little interest in further discussion. Consequently, voices within Nato arguing for unilateral confidence building steps, such as the removal of the obsolescent B61 bombs from Europe, have been muffled, and in Congress there is more support for spending money on upgrading the US arsenal rather than on disarmament.
Julian Borger
NATO revival
Putin's actions in Crimea have given Nato "a shot in the arm", said a former British defence secretary, reflecting recent widespread concern about the future of the west's military alliance.
The concern was that with Nato-sponsored combat operations in Afghanistan coming to an end this year, the alliance would have nothing to do and its west European members would make further cuts in their defence budgets. The hope in Nato headquarters is that Crimea and Ukraine will shake member governments out of what its officials regarded as complacency.
"After much agonising over Nato's purpose after Afghanistan, the Crimea crisis has given the alliance a new purpose," said Professor Malcolm Chalmers of the Royal United Services Institute thinktank in London. He added: "If Putin were to attack the territory of a Nato member state, like Poland or Latvia, other Nato states – including the UK – would be obligated to respond militarily."
Barack Obama's message during his European trip this week was that Washington would stand by its security guarantees to Nato partners, notably post-Soviet states that joined the alliance.
"We will act in their defence against any threats," he said. "That's what Nato is all about." The British defence secretary, Philip Hammond, sang from the same hymn sheet during a visit to Washington. "There should be no doubt," he said, "about our resolve to defend Nato members."
Nato will reassure its eastern allies by holding exercises and deploying fighters. The US is also using the crisis to galvanise west European Nato members to end their steady fall in defence spending. For the moment, however, there is huge relief they rejected calls for Ukraine to join Nato in 2008 when Russian was attacking Georgia over the status of Abkhazia and South Ossetia.
Richard Norton-Taylor
Will Belarus come in from the cold?
Alexander Lukashenko, the strongman leader of Russia's neighbour and long-time ally Belarus, has been cool on Crimea joining Russia, saying the move sets a "bad precedent". Belarus pointedly didn't send observers to Crimea's 15 March referendum on joining Russia, and Lukashenko has said he is ready to work with the new Kiev government, which Russia says is illegitimate.
A visit to Minsk by a Nato delegation this week seemed to send a signal that Belarus, faced by increasingly aggressive Russian policy in the CIS, could move toward the west. The delegation discussed expanding Belarus's participation in UN peacekeeping and military exercises and arms purchases from the west, as well as the possible stationing of Nato aircraft in Belarus.
But Lukashenko is a canny operator, and some believe he has no plans to leave Russia's camp – and merely wants to improve his negotiating position with Moscow.
"Lukashenko definitely wants to cash in on this crisis, and he wants to use it to make up with the west," said Yaroslav Romanchuk, a political and economic analyst in Belarus. "At same time, he wants to not quarrel with Russia too much and make Russia pay for him staying around."
The Belarusian president is at a "crucial stage" of negotiations to join the Eurasian Economic Union, the Russian-led alternative to the European Union, and Lukashenko's flirtations with the west will likely give him more bargaining power to remove trade barriers and seek a large loan from Russia, Romanchuk said. Lukashenko may also be hoping that the EU will finally recognise him as president after he runs for re-election next year.
Belarus is economically dependent on Russia and is a transit hub for Russian oil sold to Europe. Its largest single source of income is selling refined petroleum made from subsidised Russian crude.
Moscow-based political analyst Alexei Makarkin said the Nato negotiations were a way of "gently indicating to Russia that he's an independent figure". Although Europe will likely continue to encourage Minsk to distance itself from Moscow, this won't lead to any concrete agreements, he predicted.
"He needs Russia to support him," Makarkin said. "He needs to show that he's independent and that he controls entire situation in his country, that he's not an enemy of Russia."
Alec Luhn in Moscow
The siege of Londongrad
Sanctions will only hit a few individuals for now, but Russians in London have worries for the future. The overall economic relationship between Britain and Russia is changing. The time when Russians would buy up a football club or a newspaper on an apparent whim are over.
But that doesn't mean rich Russians will immediately rush for the exits. Some are predicting a subtle switch, with money pouring into art.
"When you feel yourself under the threat of financial sanctions and freezing of your bank accounts it is always easier to invest in a piece of art," said Svetlana Marich, international director of the Phillips auction house, which belongs to Moscow-based Mercury Group. "Nobody could take a painting from your bedroom even if international sanctions are imposed against you."
The multimillionaire owner of one of the most successful London restaurants, Arkady Novikov, said it would be a complete nonsense to stop doing business abroad because of the Ukrainian crisis.
"I do not think much about these sanctions. I am not a little girl to feel offended by them. Nobody tried to put pressure on me so far. Neither from one nor from the other side. I hope I will be able to continue to cheer up Russian and British audience in my restaurants in the UK and other parts of the world. Tensions will disappear, business will remain."
"Business people are always more optimistic than political analysts. Moreover, pragmatic uses of London will remain an attraction," says Alena Ledeneva, professor of politics and society at University College London. "Sanctions are narrow and hit only a limited circle of people. They are not relevant for the default globalisation process of Russian business."
Alexander Lebedev, the owner of the Evening Standard and Independent newspapers, says it would be naive to believe sanctions could prevent corrupt Russian money coming to London.
"We do not have another London to do business and invest in. British sanctions could not stop Russian kleptocracy from putting money here. As long as British lawyers are welcoming Russian dirty money and British government pays zero attention to this co-operation of Russian corruption and English law, nothing would change."
"You see only the surface of the iceberg and you see only the things we would like you to show."
Tonia Samsonova, London correspondent for the Echo of Moscow radio station
Fracking
The bustup between the west and Russia over Crimea has been seized on by those in favour of fracking shale gas in Britain as a convenient new way of selling a potentially exciting – but controversial – new energy source.
David Cameron took up the theme at a nuclear summit in The Hague this week, saying shale offered a "good opportunity" to strengthen the UK's energy self-reliance at a time of falling North Sea production.
"Energy independence, using all these different sources of energy, should be a tier-one political issue from now on, rather than tier five," he said echoing the positive noises coming out of the industry itself.
The fact is that no one really knows how much shale gas will be found in Britain and how much will be exploitable at a commercial rate.
The prime minister also overlooked the fact that numerous experts have warned that it could take many years of exploration and then development before this country has a resources that really makes a difference. Only a couple of large companies – Centrica and Total of France – have invested in the UK shale sector and their financial commitments have been tiny by their standards.
Most environmentalists – and many locals living near potential fracking sites – raise concerns about chemical and water use and remain determined to try to halt any operations.
But politicians in Europe are deeply aware that a shale gas "revolution" in North America has sent the price of natural gas spinning downwards, acting as a boost to economic activity and triggering a significant manufacturing revival.
Up until now, the national security issues around having a domestic own power supply – independent of imports – have rarely been aired in favour of other power sources such as wind farms or even nuclear stations. But just as Ukraine and Poland have encouraged a shale search to loosen dependence on Russian gas, so now seemingly has Britain - even though little gas arrives here from Siberia.
Terry Macalister
Irredentist appointment
Musing on Russia's annexation of Crimea, Strobe Talbott, foreign policy analyst and former US deputy secretary, sent an eye-catching tweet last week. He wrote: "Thanks to Putin, musty word 'irredentism', coined by Italians in 19th & early 20th century, is now all-too-relevant to new perils of 21st."
Talbott was referring to the doctrine that a country is entitled to control areas or territories outside its borders to which it has an ethnic or historical claim. The word comes from the Italian for unredeemed –irredenta. The Italians patriots who came up with it were referring to Italian-speaking territories at the time under the control of the Austro-Hungarian empire (Trieste, Istria, Dalmatia and so on). Ever since, irredentism has frequently featured in territorial disputes, especially but not always in Europe. The doctrine's most brutal exponent, of course, was Hitler. The Führer justified his annexation of Austria and the Südetenland on the grounds that he was protecting ethnic Germans and incorporating them into Greater Germany. The 1938 Anschluss in Austria took place after a rigged referendum.
Putin's audacious irredentist land-grab in Ukraine is the biggest geopolitical challenge for the west since the cold war. It has shaken the post-war consensus that Europe's borders are fixed, and has thrown up a series of major challenges for the US, the EU and Nato – defensive, cyber, energy. The question now is how far is Putin prepared to go to realise what looks like a plan to create a new Greater Russia? The obvious next target are the Russian-speaking areas of south and eastern Ukraine. Trans-Dniester – a Russian-speaking separatist territory and Soviet hangover next to Moldova – has already said it wants to join the Russian Federation. There are significant Russian-speaking populations in the Baltic states, and in post-Soviet central Asia, especially Kazakhstan.
Seemingly, the Kremlin's annexation sets a military precedent for other major states with historical grudges to take matters into their own hands. China notably abstained on a motion by the US at the UN security council condemning Moscow's annexation of Crimea. Beijing has always claimed Taiwan is part of the People's Republic of China, applying the irredentist principle that the Chinese-speaking peoples are an indivisible entity. (For its part, China has Tibet – from Beijing's point of view a separatist or splittist rather than irredentist problem.)
There are numerous other irredentist hotspots out there. Pakistan claims Indian-administered Kashmir on the grounds that it is the only state with a Muslim majority. Afghanistan's Pashtun tribes refuse to recognise the Durand line, drawn up by a British civil servant, and dividing Pakistan and Afghanistan. Argentina makes an irredentist case for the Malvinas or Falkland islands, on the grounds of historical justice and propinquity. But the population on the Falklands is resolutely British, making the ethnic argument tricky and allowing London to invoke self-determination.
What conclusions should sovereign nations draw from the unhappy Crimea affair? With irrendentism back in fashion one is surely get yourself a nuclear weapon. And hang on to it.
Luke Harding
