In 3rd debate, Democrats clash over funding Medicare-for-all

On Thursday night, the top 10 Democratic presidential candidates faced off on a debate stage for the first time, in Houston. The extended debate duration -- three hours instead of two -- enabled longer, more in-depth policy explanations. For the most part, the tone was civil, but Julian Castro's attack on Joe Biden's memory struck some viewers as overly personal and mean. Lisa Desjardins reports.