Democratic National Committee Chairman Ken Martin defended his party's big-tent approach Monday, arguing Democrats must continue expanding their coalition even as Republicans target the party over its ties to democratic socialists.Martin was pressed during an interview on MSNOW about whether the Democratic Socialists of America (DSA) is a liability for the party ahead of the midterm elections."So let me just say, I've always taken a big-tent approach to how you build a party," Martin said. "That's why I was successful for all these years in Minnesota. I believe you win through addition, not su...