They say there's safety in numbers. Europe, Nato and the US find themselves looking nervously over both shoulders these days. A) At China: the ever-present shadow over Shoulder Number One, with its economic might and expanding global influence. And increasingly: B) At Moscow, looming over Shoulder Number Two. Not "only" the threat to Ukraine's national sovereignty, but also concern about President Vladimir Putin trying hard to shift the balance of power in Europe. Geopolitics is very much on the mind of Western leaders. They fear the Kremlin is using tensions over Ukraine to divide and rule. It's a mark of just how seriously they view the situation, that oft-bickering allies are suddenly, and very publicly, in a determined "we're all in this together, singing-from-the-same-hymn-sheet" mode. The fortunes of prominent EU leaders are also being affected, in the frenzied shuttle diplomacy we're witnessing across Europe, to Moscow and Washington, as Western powers try to calm the situation and avoid a military invasion into Ukraine. I'll get to that in a moment. Firstly, there are plenty of well-known divisions between Western allies for President Putin to try to exploit, should he so wish. President Macron infamously dismissed Nato as "brain dead" not that long ago. He's been the loudest EU advocate of what he calls Europe's "strategic autonomy". Since President Donald Trump, EU-US relations have been tense over Nato defence funding and more. EU-UK relations have been strained since Brexit. And EU member states regularly quarrel amongst themselves over all sorts of things. Very much including foreign policy. But in recent off-the-record briefings I've had with high level EU diplomats - usually good for gleaning the real low-down - I've noticed a conscious change in tone. Co-operation with the US is "better than it has been in decades", I'm told. EU countries are working "extremely well with the UK within Nato" on how to deal with Moscow, and everyone is "100% on board" with a plan for tough economic sanctions on Moscow and Putin allies, should Russia take military action in Ukraine. In fact, the European Commission is engaged in sustained internal diplomacy - as it was during the Brexit negotiations at the time - in an attempt to keep the 27 member states united over sanctions. It's whispered in EU corridors, that one of the reasons a precise, written "menu" of Russia sanctions for differing potential scenarios does not exist, is that Brussels hopes less detail means less fodder for member states to haggle over and complain about. UK Prime Minister Boris Johnson commented in a UK newspaper article on Tuesday that, while the West was united in threatening sanctions, there were still "shades of opinion" between allies over what those penalties should be. "We want our friends to have sanctions ready to go," writes the prime minister. "We will continue to press for this." The European Commission too has insisted that sanctions will only work if allies take a common position. Normally EU countries are divided over Russia. Poland and other former communist countries in Eastern and central Europe tend to want to be tough on Moscow, which they constantly view as a potential security threat. They see the UK as being of the same mind, and openly still mourn the UK's departure from the EU because of this. Italy, France and Germany have often been accused by fellow EU members as being too "soft" in their dealings with Moscow; too keen on schmoozing President Putin, hungry for Russian business and, especially in the case of Germany, which has all but phased out nuclear power - Russian gas. Right now, the Kremlin insists it has no plans to invade Ukraine. But the build-up of its and Russian-allied troops on the Ukrainian border, is viewed as the biggest military build-up in Europe since World War Two. Germany raised irritated eyebrows in and outside the EU recently for refusing to send weapons to Ukraine. It was mocked by many for promising Kyiv helmets, a field hospital and 350 soldiers to be sent to Lithuania instead. And it's hardly helped Germany's reputation that former German Chancellor Gerhard Schroeder, just became nominated as a board member of Gazprom, a majority Russian state-owned energy giant. But this week, even amongst the EU's biggest Russia-critics, I was hearing that while it would be "helpful" for Germany to have a stronger, clearer line on Russia, Berlin was "doing its best" . A publicly united front to present to President Putin is clearly uppermost in EU minds. We've only just started the week, and already we've seen a whirlwind of high-level bilaterals, planned trilaterals and quadrilaterals to discuss rising tensions with Moscow. On Monday alone, the French president was with Vladimir Putin in Moscow, the German chancellor met Joe Biden in Washington and the foreign ministers of Slovakia, Austria, Germany and the Czech Republic headed together to Kyiv.