Independent central banks were once all the rage. Taking decisions over interest rates and handing them to technocrats was seen as a sensible way of preventing politicians from trying to buy votes with cheap money. They couldn’t be trusted to keep inflation under control, but central banks could.

Trump raises pressure on Federal Reserve to cut interest rates Read more

And when the global economy came crashing down in the autumn of 2008, it was central banks that prevented another Great Depression. Interest rates were slashed and the electronic money taps were turned on with quantitative easing (QE). That, at least, is the way central banks tell the story.

An alternative narrative goes like this. Collectively, central banks failed to stop the biggest asset-price bubble in history from developing during the early 2000s. Instead of taking action to prevent a ruinous buildup of debt, they congratulated themselves on keeping inflation low.

Even when the storm broke, some institutions – most notably the European Central Bank (ECB) – were slow to act. And while the monetary stimulus provided by record-low interest rates and QE did arrest the slide into depression, the recovery was slow and patchy. The price of houses and shares soared, but wages flatlined.

A decade on from the 2008 crash, another financial crisis is brewing. The US central bank – the Federal Reserve – is coming under huge pressure from Donald Trump to cut interest rates and restart QE. The poor state of the German economy and the threat of deflation means that on Thursday the ECB will cut the already negative interest rate for bank deposits and announce the resumption of its QE programme.

But central banks are almost out of ammo. If cutting interest rates to zero or just above was insufficient to bring about the sort of sustained recovery seen after previous recessions, then it is not obvious why a couple of quarter-point cuts will make much difference now. Likewise, expecting a bit more QE to do anything other than give a fillip to shares on Wall Street and the City is the triumph of hope over experience.

There were alternatives to the response to the 2008 crisis. Governments could have changed the mix, placing more emphasis on fiscal measures – tax cuts and spending increases – than on monetary stimulus, and then seeking to make the two arms of policy work together. They could have taken advantage of low interest rates to borrow more for the public spending programmes that would have created jobs and demand in their economies. Finance ministries could have ensured that QE contributed to the long-term good of the economy – the environment, for example – if they had issued bonds and instructed central banks to buy them.

This sort of approach does, though, involve breaking one of the big taboos of the modern age: the belief that monetary and fiscal policy should be kept separate and that central banks should be allowed to operate free from political interference.

The consensus blossomed during the good times of the late 1990s and early 2000s, and survived the financial crisis of 2008 . But challenges from both the left and right, especially in the US, suggest that it won’t survive the next one. Trump says the Fed has damaged the economy by pushing up interest rates too quickly. Bernie Sanders says the US central bank has been captured by Wall Street. Both arguments are correct. It is a good thing that central bank independence is finally coming under scrutiny.

For a start, it has become clear that the notion of depoliticised central bankers is a myth. When he was governor of the Bank of England, Mervyn King lectured the government about the need for austerity while jealously guarding the right to set interest rates free from any political interference. Likewise, rarely does Mario Draghi, the outgoing president of the ECB, hold a press conference without urging eurozone countries to reduce budget deficits and embrace structural reform.

Central bankers have views and – perhaps unsurprisingly – they tend to be quite conservative ones. As the US economist Thomas Palley notes in a recent paper, central bank independence is a product of the neoliberal Chicago school of economics and aims to advance neoliberal interests. More specifically, workers like high employment because in those circumstances it is easier to bid up pay. Employers prefer higher unemployment because it keeps wages down and profits up. Central banks side with capital over labour because they accept the neoliberal idea that there is a point – the natural rate of unemployment – beyond which stimulating the economy merely leads to higher inflation. They are, Palley says, institutions “favoured by capital to guard against the danger that a democracy may choose economic policies capital dislikes”.

Until now, monetary policy has been deemed too important to be left to politicians. When the next crisis arrives it will become too political an issue to be left to unelected technocrats. If that crisis is to be tackled effectively, the age of independent central banks will have to come to an end.

• Larry Elliott is the Guardian’s economics editor