The world this week
Politics Joe Biden’s campaign bounced back after he won most of the 14 states that voted on Super Tuesday. Barack Obama’s vice-president racked up big victories in southern states, where black voters are a large part of the Democratic electorate. Mr Biden earlier scored a huge win in the South Carolina primary. The race for the party’s presidential nomination is now between him and Bernie Sanders, who won California, the biggest prize on Super Tuesday. Despite a costly media blitz, Mike Bloomberg did poorly and ended his campaign; he endorsed Mr Biden. Elizabeth Warren came in a miserable third in her home state of Massachusetts. In a boost to the power of the presidency, a federal appeals court sided with the White House when it ruled that Congress had no powers to…