The cost to US consumers and firms imposed by tariffs on Chinese imports is not large relative to the gain that would be achieved if the US succeeds in persuading China to stop illegally taking US firms’ technology. But the Trump administration should state that this is the goal, and that the tariffs will be removed when it is met.

The end of the year is a good time to consider the risks that lie ahead of us. There are of course important economic risks, including the mispricing of assets caused by a decade of ultra-low interest rates, the shifts in demand caused by the Chinese economy’s changing structure, and European economies’ persistent weakness. But the main longer-term risks are geopolitical, stemming from four sources: Russia, China, the Middle East, and cyberspace.

Although the Soviet Union no longer exists, Russia remains a formidable nuclear power, with the ability to project force anywhere in the world. Russia is also economically weak because of its dependence on oil revenue at a time when prices are down dramatically. President Vladimir Putin has already warned Russians that they face austerity, because the government will no longer be able to afford the transfer benefits that it provided in recent years.

President Barack Obama has responded to the horrible actions by the forces of the Islamic State in Iraq and the Levant (Isis) and to the sharp turn in American public opinion by promising to degrade and eventually destroy this powerful terrorist group. But, not surprisingly, Mr Obama promises to achieve this without putting any American combat troops on the ground in Iraq or Syria and without any significant increase in military spending. What is happening in this battle reflects a more broadly misguided and underfunded US defence policy.

"The only way that Greece could avoid a default would be by cutting its future annual budget deficits to a level that foreign and domestic investors would be willing to finance on a voluntary basis. At a minimum, that would mean reducing the deficit to a level that stops the rise in the debt-to-GDP ratio."