Hillary Clinton takes every chance she can to highlight her foreign policy experience, and when she cited praise from Henry Kissinger for her tenure at the State Department when she debated Bernie Sanders in New Hampshire a week ago, Sanders didn’t say anything. And it bothered him. “I should have said something,” he told his chief strategist Tad Devine as they were doing their half-day of debate prep on Thursday in Milwaukee.

“Well, you have an opportunity tonight,” Devine told him. Kissinger is not a beloved figure to people like Sanders on the anti-war left who recoil from Kissinger’s Realpolitik and his cynicism in politicizing the Vietnam War. Devine showed him the line in Clinton’s book, “Hard Choices,” where she says that she sought Kissinger’s advice and approval.

Sanders called her words “rather amazing,” and with obvious delight elaborated. “Because I happen to believe that Henry Kissinger was one of the most destructive secretaries of state in the modern history of this country,” he said. “I am proud to say that Henry Kissinger is not my friend. I will not take advice from Kissinger.”

Viewers of that exchange were understandably puzzled. Kissinger, now in his early 90’s, has been off the stage for more than three decades. The young people who are flocking to Sanders have no idea who he is.

“They do now,” says Bob Shrum, who worked with Devine on the Gore and Kerry campaigns, and says the exchange reflects what Sanders believes, and who he is, more than any strategic or tactical move.

Told of Shrum’s comment, Devine said judging by the number of Google searches, people were looking for Kissinger, “And when they do, they’re not getting one of his treatises from Harvard, they’re getting Pol Pot and bombing Cambodia. They get a lot of stuff like that, and that puts Hillary on the defensive where she supposedly supremely rules.”

In their after-action assessment, the Sanders campaign was pleased with the back and forth on Kissinger. “Whenever you can put your opponent on the defensive in a debate, that’s good,” says Devine. “I didn’t see her embrace Dr. Kissinger the way she embraced the President.”

He went on to make the point that Sanders makes repeatedly, that Clinton has extensive experience in foreign policy, that’s indisputable, but there are differences between them on judgment. Sanders opposed the first Gulf War, and the war in Iraq, and while he voted for the war in Afghanistan, Devine said that he has privately “expressed great reservations, and if he could do it over again, he would only support a resolution.”

Sanders did support intervention in Kosovo and in Serbia, votes that he uses to argue that as president he would use force in a responsible way. He disagrees with Clinton on a no-fly zone in Syria and has been critical of the administrations intervention in Libya. “She’s more of an interventionist, which she’s been promoting for many years,” and she made the same critique against Obama in ’08 as being “naïve” about engaging with foreign enemies that she’s making against Sanders.

“There are big differences between them and Kissinger is really the embodiment of those differences. He’s the father of the neo-cons and their use of force.”

Devine seems almost amused that the Kissinger sound bite has gotten so much traction. “We’re happy to have that debate, but are we going to go out and create a campaign about the nuances of foreign policy? No we’re not,” he says. Just as Sanders on the debate stage pivots quickly to the message that has made him a serious contender, Devine says the campaign is about an economy that is rigged, and that rigged economy is held in place by a corrupt system of finance, “the result is enormous income inequality. We think that’s where the voters are.”