It’s a rare treat to hear the phrase “Writing in the Guardian, David Cameron says” on the morning’s news bulletins before being told that the prime minister is warning us sandal-wearing polenta eaters of flashing red lights ahead for the global economy.

That’s not so good, but it is mostly true, as Larry Elliott explains in his analysis of Cameron’s statement.

What’s not good either is to be told a few seconds later that Labour is accusing Cameron of “making excuses” for his own economic failures. There’s an element of truth in that, as there would be if Labour still occupied 10 and 11 Downing Street and was saying similar things – as it would be (and did) – before a tricky election.

But it ignores the larger fact that, as Cameron writes, that the UK economy is recovering. It is fragile, patchy and unfair in many ways, but it is also in better shape than most of our EU neighbours. Saying, as Ed Miliband did again in his “zero-zero” Senate House speech last week, that “Britain only works for the privileged few” is palpably not the case and therefore unwise.

It is not Cameron’s fault that the eurozone looks like stumbling into a third bout of recession, it really isn’t. We should be grateful for his cross-party alliance with Gordon Brown (not Tony Blair or Nick Clegg) to keep sterling out of that death trap. If other aspects of Tory policy towards Europe were not so idiotic – and more so by the day – it might be wholesome to point out this constructive achievement of much-maligned Westminster politics occasionally.

And no, it is not Cameron’s fault that surplus-trader China, which gallantly boosted domestic demand (as Germany did not) after the 2008 banking crisis, is slowing down and now has a not-unrelated debt hangover of its own. Likewise Japan. Sorry, Ed, but we cannot blame George Osborne for its long stagnation and the likely failure of the breakout strategy known as Abenomics. And let’s not blame Dave for the destructive stalemate between the lacklustre Obama White House and a know-nothing Congress either.

It is always important to distinguish between what the government IS responsible for and what is beyond its reach for a raft of reasons. If we do not, we slip into casual, often lazy and ignorant, cynicism whose walking embodiment is Nigel (“Mine’s a pint”) Farage, the nation’s saloon pundit. “Drinks all round, they’re on the European taxpayer.”

Cameron, Osborne and crew can be blamed for the shape of UK tax and spending policies, though not for the Bank of England’s (and US Federal Reserve’s) monetary policy, which has helped keep the wolves of recession at bay. They can be blamed for the harsh, self-defeating bedroom tax, but not for the wider drive to curb the fiscal deficit and debt mountain: the bankers are mostly responsible for that and some of them should be in jail.

You can do the exercise yourself, though my tip is to avoid the temptation to blame either Labour (1997-2010) or the coalition (2010-) for deep-rooted weaknesses in the structure of pension provision or the failure of the school system to educate and motivate our children to take those jobs being grabbed by eager foreigners. These problems are a long time in the making and the curing. We do make slow progress, not always visible right away.

The truth is always that national governments usually have less room for manoeuvre than contending parties claim. That is as true of Ukip or the currently successful SNP government in Edinburgh as it is of the tired major brands. Determination and strategic vision, not to mention low cunning, can achieve a lot – as Margaret Thatcher and Alex Salmond have both demonstrated.

Yet the problems they claimed to be able to solve are still there, sometimes in different forms they created themselves, and will be even if clever Nicola Sturgeon manages to achieve independence for Scotland. Just as it is not Dave’s fault that the eurozone is in trouble, it is not Alex’s that the world price of oil has dropped by one-third since the summer – though leaders of an oil-dependent Scotland would have to deal with it, another of those outside-our-control problems like Islamic State and Ebola.

So Chris Leslie, the Labour economics spokesman who accused Cameron of making excuses, was only doing what opposition spokesfolk do when shooting from the hip. It was fine to attack the Tories over the European arrest warrant (EAW) vote shambles last week – as I wrote at the time – because it was a shambles of their own making. It’s not so fine to jeer simply because borrowing is much higher than Osborne expected by 2014.

The borrowing helps pay the social security bill, which eases the distress of those in most need at a time when tax receipts – from individuals and companies – are disappointing, so the gap widens. Low wages and falling profits are a major factor, alongside the familiar issues of tax avoidance and evasion. By all means blame the Tories for the bedroom tax, blame pious Iain Duncan Smith in particular, but not for the tsunami of problems that threatens to engulf us all. We shall overcome, but it will require warm hearts and cool heads.