DUBUQUE, Ia – Democratic presidential candidate Bernie Sanders, flashing some irritation, told reporters Sunday night that he was determined not to attack his chief rival for the party’s nomination, front-runner Hillary Clinton.

“Time after time I’m being asked to criticize Hillary Clinton,” the Vermont senator said after a rally attended by 2,000 people at a local college. “The reason this campaign is doing well is because we’re talking about the issues that impact the American people.”

“I think the American people are sick and tired of politicians saying, ‘I’m great, everyone else is terrible,’ ” he said Sunday.

But he has found a way to get a message to primary voters that Mrs. Clinton isn’t the candidate they want to win the White House.