How It All Came Apart for Bernie Sanders

In mid-January, a few weeks before the Iowa caucuses, Sen. Bernie Sanders' pollster offered a stark prognosis for the campaign: Sanders was on track to finish strong in the first three nominating states, but Joe Biden's powerful support from older African Americans could make him a resilient foe in South Carolina and beyond.The pollster, Ben Tulchin, in a meeting with campaign aides, recommended a new offensive to influence older black voters, according to three people briefed on his presentatio