Sanders, O'Malley face protesters at Netroots Nation conference

Sen. Bernie Sanders addresses hecklers and supporters at the Netroots Nation Presidential Town Hall in the Phoenix Convention Center on Saturday.The annual Netroots Nation political conference, being held here this year, isn't just supposed to be friendly to progressive candidates. It is an applause-filled jaunt that can add luster to campaigns whose candidates want to be standard-bearers of the liberal wing of the Democratic Party.

That was far from the case on Saturday, the showcase day of the five-day event that began Wednesday, as former Maryland Gov. Martin O’Malley and Sen. Bernie Sanders of Vermont found themselves face-to-face with protesters, led by supporters of the "Black Lives…