E.J Dionne: Warren’s plan worked. Now she needs another one.

Washington • For Elizabeth Warren, the hard part begins now.The Massachusetts senator is unquestionably the front-runner for the Democratic presidential nomination, which made her the focal point of attacks from her rivals in Tuesday’s Democratic debate. Former Vice President Joe Biden had an easier time of it, but this was not good news for him. At various points in the three-hour marathon, he faded away. His rivals no longer see him as the person to beat.Beneath the jostling for pos