Senior diplomatic figures have said a potential deal exists in which Vladimir Putin would de-escalate the troop build-up along the Ukrainian border, which is driving tension with the West.
Russia has sent more than 100,000 troops to it western borders with Ukraine, deployed in as many as 60 military battle groups for exercises. While Russia insists it has no plans to invade, Washington and its allies have said an onslaught is likely.
They are preparing a package of sanctions in an attempt to persuade Mr Putin against his current course.
What does Vladimir Putin want in Ukraine?
Mr Putin has signalled his wider agenda of overhauling the post-Cold War order with the US-led European alliance. Nato members have in return said they are determined not to allow the international borders in the region to be redrawn by force.
Russian Foreign Minister Sergey Lavrov and US Secretary of State Antony Blinken met in Geneva last week for a dialogue on how to resolve the Kremlin's push for changes in the security regime across the continent.
Sergey Ryabkov, the deputy Russian foreign minister, outlined the bottom line: “For us, it’s absolutely mandatory to make sure that Ukraine never — never ever — becomes a member of Nato.”
Another focal point of the talks is the revival of the Nato-Russia Council as part of an overall package.
In a note for the Chatham House think tank, Sir Roderic Lyne, a former British ambassador to Moscow, and Sir David Manning, a former ambassador to Washington, said this strand was a way forward.
“The US could also re-establish a regular security dialogue with Russia, perhaps with an agreement that the two parties would give briefings on it to the Nato-Russia Council,” the note said.
“In the longer term, once the immediate threats to security are resolved, Nato could then express willingness to consider a wider new negotiation on European security architecture.
“The second subject for negotiation — and probably the most difficult — is Russia’s relationship with Ukraine.
“There must be a peaceful settlement of the conflict on Ukraine’s eastern border but Nato must stand rock solid on the sovereign independence of Ukraine.
“It cannot agree to any provision which allows Russia to limit that sovereignty and it cannot negotiate over the heads of the Ukrainians.”
How would Ukraine be affected?
There would be some pain for Ukraine in the process as Russia has pressed its demands for autonomy for areas controlled by separatists in the eastern part of the country since 2014.
A ceasefire deal known as Minsk II was agreed upon in 2015 by the leaders of Ukraine, Russia, France and Germany to work towards ending the conflict in Ukraine’s Donbas region. Officials from those countries are due to take part in consultations organised by French President Emmanuel Macron on Wednesday in Paris.
“The outlines of a settlement already exist but the Minsk II proposals are not acceptable and should be amended,” said the Chatham House note.
“Ukraine and Russia should withdraw forces from the border zone, with credible border monitoring perhaps by UN peacekeepers.
“Donetsk and Lugansk should remain within Ukraine and return to administration by Kiev, with constitutional changes to grant them a greater degree of autonomy but, most importantly, without external involvement.”
Is conflict between Russia and the West inevitable?
Another think tank, the Centre for European Reform, said that poor relations with Moscow should not be regarded as guaranteed even as countries like the UK look to firm up their policies.
“The UK should not shut the door on the possibility of better relations,” it said in its latest bi-monthly bulletin.
“Disagreements between London and Moscow will need to be managed through dialogue; and there are still a few issues, such as non-proliferation and counterterrorism, on which London and Moscow might be able to co-operate.
“And the UK should continue to promote educational, scientific, sporting, tourism and mutually beneficial trade links with Russia, to underline that the UK’s problems are with the current leadership and its policies, not with the Russian people.”
Can talks between Russia and Nato be successful?
Writing for the forum European Leadership Network, Kevin Ryan, a retired US brigadier general who is now a fellow at Harvard Kennedy School’s Belfer Centre, said two draft treaties handed to the West by Russian diplomats indicated the country had rushed to get the talks going.
He said negotiations and better drafting could produce a positive outcome for both sides.
“If the Russian side is sincerely seeking a diplomatic resolution to its security needs, it could suggest that a well-co-ordinated and coherent counterproposal from the US and Nato might achieve some long-term security guarantees for our own vital interests,” he said.
“Nato and the US are working from a position of strength relative to Russia. They have a unique opportunity to set the conditions for security in Eastern Europe for the long term. To achieve this goal, however, it is necessary to acknowledge that Russia has legitimate security concerns about Nato enlargement.
“The US and Nato should combine the two Russian proposals and counter it with a united proposal that addresses Russia’s concern about Nato expansion, rolls back Russia’s own expansion in its near abroad, and creates stable and successful states in the space between Nato and Russia.
“And the countries at the centre of this negotiation, Ukraine and Georgia, should be parties in signing the agreement.”
Would Putin stop at Ukraine?
Taking a divergent view, Oleksandr Danylyuk, the former head of the Ukraine Foreign Intelligence Service, said Moscow's ambitions stretched far beyond a reform of European security arrangements both within and beyond Nato agreements.
“By demanding an end to further Nato enlargement and a ban on Ukraine's accession to Nato, Russia is not seeking to enhance its own security,” he wrote in a commentary for the Royal United Services Institute.
“Instead, it is seeking recognition of its right to intervene, including militarily, in countries that Moscow believes remain its colonies.”
How can the West respond if Russia invades?
UK Prime Minister Boris Johnson said on Tuesday that Russia would face a fast response from the US and its European allies, including economic penalties.
“We have to calculate and calibrate what we do very carefully and I think building a strong package of economic sanctions, continuing to supply defensive weaponry and all the other things that we’re doing, that’s the right package,” he said.
Diplomats see a move to disconnect Russian financial institutions from the international payments system, the Swift network, as a nuclear option to heavily penalise the country's economy.
Commercial relations between Russian companies and western companies as well as payments transiting through Western banks would be upended.
Instead of exchanging through Swift's automatic channel, Russian banks would be forced to switch back to manual mode, using fax or email, which would involve additional transaction processing times, more risk of errors and disputes, with a sudden brake on international transactions involving Russia.
