EVEN before Plato conceived the philosopher-king, people yearned for clever, dispassionate and principled government. When the usual run of rulers proves cowardly, indecisive or discredited, turning to the wisdom and expertise of a technocrat, as both Italy and Greece have done in recent days, is particularly tempting.

Part of the attraction of the term “technocrat”, however, is that the label is so stretchy. Does it mean just any expert in government, or one from outside politics? How many technocrats, and in which positions, justify a government's “technocratic” label? Does such an administration operate within the political system, or supplant it? For how long? Can a technocrat evolve into a politician and vice versa? The answers are imprecise and shift over time.

Technocracy was once a communist idea: with the proletariat in power, administration could be left to experts. But the appliance of science to politics was popular under capitalism too. A fully fledged Technocratic movement flourished in America in the inter-war period: it believed in an economy based on measuring energy inputs rather than prices, and in what would now be called crowd-sourced solutions to political problems. This paper first used “technocracy” in March 1933, when a book reviewer bemoaned the “lurid prominence” of the term. He derided its proponents as “half-scientist…half-charlatan”, decried their “indefensible” conceptual basis, and ascribed their popularity to “extraordinary” American credulity. Howard Segal, an historian at the University of Maine, says the movement imploded when its leading light, Howard Scott, was unmasked as a failed wax salesman, not the great engineer he claimed to be.

Mandarin classes

Crankishness aside, technocracy and autocracy have long been natural bedfellows. When political power is not publicly contested at all, electability is irrelevant and expertise can give the ambitious an edge. In China all but one of the nine members of the Politburo Standing Committee are engineers. This marks a shift: many of Mao's revolutionary generation had no higher education at all. And it may be temporary. Li Keqiang, likely to take over from Wen Jiabao as prime minister in 2013, has degrees in law and economics. Other upcoming leaders are similarly schooled.

Such unconstrained technocracy is no guarantee of good ideas or decisions. China's engineer-kings threw their weight behind the Three Gorges dam, for example, despite the prophetic advice of some more eminent scientists. In the SARS epidemic in 2003, the technocrats were initially inept too, putting face-saving ahead of epidemiology. A rapid rollout of China's high-speed rail network was followed in July by a slowdown after a fatal train crash: technocracy did not prevent corruption and poor quality-control.

It is not only one-party states that like technocracy. Military officers justifying a coup may use technocratic parlance when they highlight their independence of lobbies and their focus on the national interest. Such juntas often also bring civilian technocrats into government, or hand over to them when they step down. A common outcome is a technocratic-military hybrid where civilian experts have the economic and social portfolios, but military men the defence and interior ministries (Egypt's current regime resembles that too).

Singapore is perhaps the best advertisement for technocracy: the political and expert components of the governing system there seem to have merged completely. British-ruled Hong Kong would be a runner-up. The leadership of Mexico's Institutional Revolutionary Party (PRI) has evolved from revolutionary generals to lawyer-politicians and finally economist-technocrats, but with less success.

Countries where electoral mandates are the ultimate source of political legitimacy usually turn to full-scale technocratic governments only for a short time, under a specific mandate and in unusual circumstances. But even outside such cases, technocrats rule big chunks of public life: central bankers are one example, typically enjoying huge constitutional protection from politicians' interference. So are regulators and, in a sense, the unsackable legal experts who work as judges.

Even highly political governments set up independent or bipartisan panels to make difficult decisions (such as closing military bases, setting electoral boundaries or making spending cuts). They create independent agencies to run everything from health care to education. They put outside experts in top jobs—such as the economist Larry Summers in the Clinton and Obama administrations.

Even a wholly technocratic government can never fully escape politics. In any country powerful lobbies bargain and wrangle. In a parliamentary system technocrats must deal with the partisanship and intrigues of an elected legislature (in Athens and Rome, lawmakers are eagerly waiting to trip up the newcomers). They also face public ire if they are seen as sharing out gains or pains unfairly. A brilliant economist see exactly the needed fiscal adjustment. But deciding how and where to cut spending or raise taxes requires acute political senses. Few technocrats arrive in office with those; learning them can be a slow, costly and politically fatal process.

To overcome these obstacles, a technocratic head of government needs personal stature: such clout makes up for the lack of a formal electoral mandate. A second important condition is a clear external constraint, widely accepted at home by both the public and other political parties. This can be meeting the tough conditions of an IMF bail-out or surmounting some other financial crisis. It can also be joining a club: several ex-communist countries turned to technocratic governments as they struggled to meet the membership standards set by the European Union. Failing that, political backing at home—usually from a popular monarch or president—can give a technocratic government political ballast.

Cincinnatus redux

The best kind of technocrat is uneasy about being in power at all. Jan Fischer, the Czech Republic's chief statistician, became an acclaimed prime minister in 2009 when the government collapsed in the midst of the country's six-month stint running the European Union. His main message, he says, was to tell everyone to “protest against this kind of government”; it was a lamentable departure from normal democratic principles, justified only by the most serious circumstances.

History suggests that technocrats do best when blitzing the mess made by incompetent and squabbling politicians. But the problem for the new leaders of Greece and Italy is that the source of their woes, the euro zone's design flaws, stems from mistakes made in Brussels—not least by other unelected experts. Remedying that will take many years, far longer than technocrats' usual political lifespan. And it will need more than just brains and integrity.