Chicago Tribune :Fighting for a victory just days before Nevada’s caucuses, Hillary Clinton took one of her toughest shots at rival Bernie Sanders, questioning the long-time independent’s devotion to the Democratic Party he’s running to lead.Clinton accused Sanders of attacking the two most recent Democratic presidents – President Barack Obama and her husband, former President Bill Clinton – both of whom remain popular political figures among Democratic voters.”I just don’t know where all this comes from,” she said, at a televised town hall meeting hosted by MSNBC in Las Vegas on Thursday night. “Maybe it’s that Sen. Sanders wasn’t really a Democrat until he decided to run for office.” “Well, it’s true. It’s true,” she exclaimed, amid a sprinkling of boos from the audience.”I was asked to comment on Bill Clinton’s very strong criticisms of me,” Sanders told the 350-person audience. “I didn’t go around attacking Bill Clinton.” And he noted, drawing some audience grumbling of his own, that only one candidate in the Democratic race ran against Obama, before offering a strident defense of the president, saying that much of the Republican opposition to his administration was driven by racism.”No one asks me whether I’m a citizen or not … my father came from Poland,” he said. “What’s the difference? Gee, maybe the color of our skin.”Both candidates are working to woo minority voters, a key plank of the Democratic party, ahead of Saturday’s Nevada caucuses. In the town hall meeting, they vowed to make reforming the country’s immigration system a top priority of their administrations, should either win the White House. Clinton said she’d take up the issue in the first 100 days of her presidency, a vow she’d previously refused to make.But they also answered some tough questions. Clinton was pressed on why she has refused to release transcripts of the paid speeches she delivered to some of the country’s largest financial institutions. Clinton said she’s happy to make those available – as long as other candidates do the same. “I’m happy to release anything I have whenever everybody else does the same,” she said. “Every other candidate in this race has given speeches to private groups, including Senator Sanders.”Clinton is hoping to use a win in Nevada as a springboard into races in South Carolina on Feb. 27 and a slate of Southern primaries on Super Tuesday, where she’s favored because of her strength among African-Americans.