Tensions are still running high over the Ukraine crisis, but the West's response is one clearly driven by realpolitik.

At the United Nations yesterday, Ukraine's ambassador, Yurii Klymenko, issued a warning that Russia may be preparing a "full blown military intervention in Ukraine's east and south".

Alarming as Mr Klymenko's claim is, short of that actually happening, the continuing response of the West was summed up by German Chancellor, Angela Merkel, who could only re-emphasise that Russia will face escalating EU sanctions if it does not take steps to ease the tension over Crimea.

Looking at the crisis from Moscow's perspective, its intervention in Crimea looks to have been a low-risk, cost-effective action that at the very least helped staunch the impression that Russian power is being eroded.

While it gave Western leaders the opportunity to cry "bully", at home, it presented Russian President Vladimir Putin with a win-win scenario that has bolstered his standing.

If this is the position that the Kremlin now finds itself in, what then of the political and diplomatic countermoves the West is already implementing or has at its disposal?

Three issues come to mind in this regard. The first concerns what the next steps are for German foreign policy. The second is what Washington sees as an appropriate response. Last but not least, is what Russia's invasion of Crimea means for the Nato alliance.

So far, Mrs Merkel's policy has been to try to straddle the divides, between Russia and the EU.

It's all very well for the German Chancellor to insist Russia "will not get away" with carving off Crimea. Clearly, though, she is at odds with Prime Minister David Cameron that the annexation should act as a trigger for a new level of economic and trade sanctions, known as "phase-three" in EU jargon.

This will obviously be a thorny issue at the latest EU summit in Brussels, given that Germany is heavily economically dependent on Russian gas and oil imports whereas Britain is not.

Looking across the Atlantic meanwhile, de-escalation seems to be the order of the day in Washington. So far the US response to events in Ukraine appears to have been focused on trying to contain the crisis and stabilise the situation.

According to some White House watchers, this, in great part, is motivated by the importance the Obama administration places on other global flashpoint scenarios, such as Syria, and trying to halt Iran's nuclear weapons development programme.

Some diplomatic analysts point out that the US State Department is all too aware of how pivotal Moscow is in any talks with the regimes in Damascus and Tehran, therefore despite Russia's recent bullish behaviour over Ukraine, it remains diplomatically expedient to keep Moscow on board.

If Mr Putin were to go further over Ukraine, however, all this might change and even the "big slugs of sanctions" referred to by one senior State Department official in an interview with the influential US-based Foreign Policy magazine, might not be a sufficient response in the eyes of some American officials.

This brings us to the question of what Russia's invasion of Crimea means for the Nato alliance. Critics of the West's feeble response over Crimea say it signals the fracturing and potentially ultimate demise of Nato.

At the very least it has been a wake-up call for the 28-member alliance, admitted Nato Secretary General Anders Fogh Rasmussen this week.

Mr Rasmussen went on to warn of the clear risk that "Russia will go beyond Crimea and the next goal will be the eastern provinces of Ukraine". This, he said "would have severe consequences".

Exactly what Nato would be willing to do about this however is another question entirely. The organisation itself has been faced with internal wrangles and challenging times in recent years. Privately, some within the West's corridors of power have increasingly questioned its relevance, and this coming too at a time when many of the alliance's members struggle with massive defence spending cuts.

In the immediate wake of Russia's annexing of Crimea, Nato's leaders in the first instance face the daunting task of reassuring nervous alliance members such as Poland, who share borders with Russia.

Given these factors, the crisis in Ukraine has, in effect, highlighted something of a foreign policy divide in Europe. Those eastern European countries close to the buffers with Russia are extremely uneasy; those farther away far calmer.

Yesterday, UN Secretary-General Ban Ki-moon said tension between Ukraine and Russia poses "great risks to the countries themselves and beyond" and urged restraint by all parties in a crisis that could spin out of control. The war of words and sanctions meanwhile between the West and Moscow stepped up a gear driven by a realpolitik on both sides. Let's hope it stays like that and escalates no further.