Peggy Noonan on Trump's attack on the Clintons, Sanders' new strategy
Donald Trump has declared Bill Clinton "fair game" as he takes on Democratic presidential candidate Hillary Clinton. CBS News contributor Peggy Noonan joins "CBS This Morning" to break down what this could mean for the future of Trump and Clinton's campaigns. She also discusses whether Trump has the staying power to win the Iowa caucuses and Bernie Sanders can appeal to Trump supporters.