Once Sen. Bernie Sanders (I-VT) started talking about former Secretary of State Henry Kissinger’s policy in Vietnam during Thursday night’s Democratic presidential debate, a moderator could be heard sighing “Oh God” into her microphone.

Sanders and his rival Hillary Clinton had been debating foreign policy when Sanders attacked her for taking advice from Kissinger. The senator didn’t stop the onslaught after Clinton said that she takes advice from a “wide variety of voices” with foreign policy expertise.

“It’s just a very different historical perspective here,” Sanders said. “Kissinger was one of those people during the Vietnam era—”

Then as Sanders took a breath, a moderator was caught on the microphone saying “Oh, God.”

Listen below:

h/t: Gawker