The old cliché that ‘nothing happens in August’ has again been brutally disproved. From the centenary of the outbreak of the first world war to the Russian invasion of Georgia six years ago, August is a month often packed with violence — but rarely more so than this year.

In Syria, Christians are being crucified for refusing to convert to Islam. In northern Iraq, there are reports of mothers throwing their children from mountains rather than leaving them to the jihadis who are parading the severed heads of their victims. Russian convoys are rolling towards the Ukrainian border as Vladimir Putin tests the resolve of the West. Barack Obama has watched this unfold from his holiday spot in Martha’s Vineyard; David Cameron from the Portuguese coast. The problem is not that our leaders have holidays. It is that the West lacks any real leadership at all.

Here, at home, there is pressure to recall parliament over the crisis in Iraq. Plenty of parliamentarians feel angry about what is happening, but few have any clear idea of what to do in response. Liam Fox, the former defence secretary, says that Isis must be defeated militarily and that a ‘half-hearted and ineffectual intervention’ will not do. Perhaps so, but Britain does not have a good recent record of effectual interventions — our army was driven out of Basra by a far less well-equipped group of jihadists, and who would be brave enough to suggest that our intervention in Afghanistan was a success?

After his re-election in 2012, Barack Obama declared that ‘a decade of war is now ending’. David Cameron sounds rather hawkish by comparison, even talking about the need to close down ‘ungoverned spaces’ in the Sahara desert. This is commendable, but even his own parliament struggles to take him at his word when the military budget has been slashed under his watch.

Last month, a new aircraft carrier was launched in Fife: the HMS Queen Elizabeth. Such events showcase a country’s might, and its willingness to project force. But the F-35 aircraft on its deck was a plastic replica: the real fighters are behind budget and won’t be ready until 2018. It was the perfect metaphor for Britain’s hamstrung role in world affairs.

To date, Britain’s response to the crisis provoked by Isis forces has been to airdrop humanitarian supplies, which may or may not reach their intended Yazidi recipients. America’s response has been more of the same, along with some targeted strikes on certain Isis positions. But beyond this the western world continues to show itself unenthusiastic about any clear course of action, let alone about adopting any wider strategy.

The same uncertainty and inertia dog the West’s response to Putin’s expansionist ambitions. Until fairly recently, the world powers had operated on the idea that national borders should be respected — which is why Turkey’s 1974 occupation of Northern Cyprus, ostensibly to protect Muslims, was recognised by no one. As Putin is finding out to his delight, this rule no longer seems to hold. He has effectively annexed Crimea, on the pretext of protecting Russian speakers, without paying any real penalty — military or diplomatic. He has found that Europe’s dependence on his oil is enough to override any quibbles about territorial appropriation. So now he has decided to go a step further, trying his luck by sending a convoy of 280 trucks to pro-Russian rebels in eastern Ukraine, all the while insisting that they contain ‘humanitarian aid’.

It is at the United Nations that the vacuum of leadership is most apparent. The UN was set up to embody a world order where nations would respect each other’s borders and the horrors of genocide and ethnic cleansing which scarred the 20th century would be consigned to history. It is the UN which has for 20 years spoken of a ‘responsibility to protect’ those who may fall victim to religious or ethnic cleansing. Yet it is the same UN which has most startlingly failed to function as an effective bulwark against such occurrences. The Yazidis are stranded and starving in the mountains, the Christians fleeing south, but none of the suffering tribes expects the UN to help. As has been proved in Srebrenica, Rwanda and a long list of other places, the UN lacks the coalition-building capability, the speed and the resolve to stop atrocities.

At a national level and an international level we see a leadership void, one which terrorist groups and rogue dictators are happy to fill. The western powers all hoped — and budgeted — for a quieter world. Now terrible threats are mounting before the world’s eyes and the West finds itself in a position of hitherto unimaginable weakness.