“The awakening Democratic presidential primary, with 14 declared candidates and at least nine possible more, amounts to a stark choice over the party’s future: left or center, identity-issue minded or pluralist, radical or incrementalist. In fact, we haven’t seen Left battle lines so dramatically etched for more than half a century, since 1967 and 1968, under the dual weights of a disastrous foreign war and a rising new generation determined for change. The hero of that Democratic primary, who pushed Lyndon Johnson out of the race, ignited the energy of America’s young, and set up the new fault lines along which the future of the party got fought, was Eugene McCarthy, Democratic-farmer-labor senator from Minnesota. For many of us who were part of the McCarthy campaign, it’s a new Gene McCarthy—not in form, but in values—that we want today. For those who didn’t live it, it’s hard to imagine the…