A Republican president with dwindling popularity and financial market turmoil threatening to spill over into global economic decline: 2008 has at least a few echoes of 1930. Most striking of all, now as then, protectionist rhetoric is cranking up among American politicians.

Both on Capitol Hill and in the presidential primaries, the Democrats in particular are lining up to criticise past trade liberalisation for imperilling American workers, with Hillary Clinton calling for a time-out on new deals.