The Obama administration's first real test on trade policy has arrived. The US must decide whether to impose new import restrictions on Chinese tyres under what is known as its “China safeguard” law.

This decision is not just a test of President Barack Obama's support for free trade. History could well record it as the defining moment when the multilateral trading system was able – or not – to withstand the crisis-provoked protectionist forces that currently threaten to bring it down.

The World Bank-sponsored Global Antidumping Database suggests that, since the economic turmoil began, countries have been ganging up to use World Trade Organisation rules in an almost mob-like response to restrict imports from China. The tyres case could make this far, far worse.