Hillary Clinton has broken ranks with President Barack Obama on the environment for the first time in the 2016 election campaign, saying the Arctic should not be exploited for offshore oil the day after the Obama administration gave Royal Dutch Shell a drilling permit. The Arctic state of Alaska is a battleground in the US debate over energy development and environmental protection and Mrs Clinton on Tuesday staked out a position to the left of the president by tweeting that drilling there was too dangerous to risk. Her stance is one of the few cases where the Democratic presidential contender has publicly disagreed with Mr Obama, her rival for the nomination in 2008, since stepping down as his secretary of state in 2013.