With invasion threat in limbo, the West asks itself again: What does Putin want with Ukraine?

As the threat of an invasion of Ukraine again appeared to slip into a holding pattern, western leaders and diplomats were left scrambling Tuesday to interpret conflicting signals coming out of Moscow.

Famously described by Britain's wartime prime minister Winston Churchill as "a riddle, wrapped in a mystery, inside an enigma," Russia put its willingness to play by its own rules on full display with a token withdrawal of some troops exercising in Crimea and the offer of renewed security dialogue with the West.

Russia made those gestures after several days of delivering sharp anti-western rhetoric — and after allied intelligence sources warned again that an invasion could happen as early as today.

NATO Secretary General Jens Stoltenberg pointed out that — notwithstanding the messages coming from the Kremlin — Russia still has more than 100,000 combat-ready forces poised on Ukraine's border.

"There are signs from Moscow that diplomacy should continue. This gives grounds for cautious optimism," Stoltenberg said ahead of a meeting of the Western alliance's defence ministers.

"But so far, we have not seen any sign of de-escalation on the ground."

Over the past several months, NATO has seen Russia move troops and equipment into the region, move them out while leaving their equipment behind — then move them back in just as quickly.

"So the movement of forces, the movement of Russian capabilities doesn't represent real de-escalation, but we will monitor, we will follow what they are doing," Stoltenberg said.

Following the movements of the Russian military may be the easiest part of figuring out where this crisis goes next.

President of Finland Sauli Niinisto recently sat for an interview with the New York Times about his enduring dialogue with Vladimir Putin. He told the Times he noted a change in the Russian president's "state of mind, decisiveness" during a recent long conversation. He said he believed Putin felt he had to seize on "the momentum he has now."

That sort of nuance is missing from the political and diplomatic calculus of the West, said veteran Canadian diplomat Colin Robertson.

"It comes down to Putin because he has a view of history that sees the greatest catastrophe of the 20th century being the dissolution of the Soviet Union," said Robertson, a vice-president at the Canadian Global Affairs Institute.

"And I think, before he leaves, he's determined to restore as much of that as he can. He's in his late 60s now and I think he's determined to do it before he leaves — bring Ukraine back into Russia by force, if necessary, preferably by bluff."

Russia's parliament, the Duma, attempted to further dismantle Ukraine on Tuesday by voting in favour of a motion calling on Putin to recognize as independent republics the breakaway regions of Donetsk and Luhansk, where Russian proxy forces have been fighting Ukrainian soldiers.