Republicans and Democrats are trading blame for the impasse on a temporary bill to keep agencies open as the US government teeters on the brink of a partial shutdown.

An angry Barack Obama defended his tax deal with Republicans and hit back at critical fellow Democrats, warning them against becoming too ideologically pure and self-satisfied.

DISENCHANTED voters in both parties turned against the establishment, choosing a conservative “Tea Party” newcomer over a handpicked Republican favourite and dumping veteran Democratic Senator Arlen Specter ahead of November’s midterm elections.