As the South Korean hostages held by Afghan rebels begin a third week of incarceration, the crisis is causing a new outpouring of anti-American sentiment in Seoul and is reshaping the political debate in the run-up to presidential elections.

Over the past fortnight the nation has swung between despair over the Christian aid workers’ plight at the hands of the Taliban Islamist militia, and anger that they went to such a dangerous land in the first place.