Buoyed by a half-hour prime-time television advertisement watched by 26m Americans and an endorsement from former president Bill Clinton, Barack Obama on Thursday embarked on the final stretch of the presidential campaign with appearances scheduled in eight key states by Monday night.

Paid for by the Democratic candidate’s campaign and aired on seven network and cable stations, the “American Stories, American Solutions” advert eschewed attacks on John McCain, the Republican, and focused on portraying Mr Obama as being in touch with the concerns of ordinary Americans.