Obama turns focus to U.S. Congress as he campaigns for Clinton

President Barack Obama on Sunday campaigned in the battleground state of Nevada for Hillary Clinton, the Democratic candidate he wants to succeed him in the White House - but he spent most of his time talking about the state's Senate race. Democrats badly want to get back control of the Republican-controlled Senate in the Nov. 8 election, and are sending Obama, Michelle Obama and Joe Biden to states where close races could tip the balance. In Nevada, Obama reserved most of his firepower for mock