Weary delegates return to table after deadline is extended, but 'path forward is really unclear'

US President Barack Obama's willingness to extend Iranian nuclear talks at least twice this week has laid bare the dilemma he faces as he pursues a high-stakes accord.

Walking away from negotiations would strip Obama of a legacy-shaping deal, deeply complicate international efforts to stop Iran's suspected pursuit of a bomb, and perhaps raise the specter of US military action against Teheran's nuclear installations.