So was the week in Washington a good or a bad one for free trade? That depends on whether you care about symbolism or substance.

The optimistic symbolists are celebrating the congressional progress of bilateral US trade agreements with South Korea, Panama and Colombia, which have languished unratified for half a decade. The realists who prefer substance note with concern a bill aimed at punishing China for undervaluing the renminbi – which, as even the painfully circumspect White House is finally pointing out, is vulnerable to legal challenge at the World Trade Organisation.

One popular theory is that some lawmakers feel compelled to support the currency bill to establish China-bashing credentials, after provoking the wrath of protectionist voters by backing the bilateral deals. If this is the implicit trade-off, it is a strikingly bad bargain. It risks opening a new and litigious front in the international currency wars, with a potential impact on the entire global economy, just to jam through three preferential trade agreements of minor commercial importance.