Vilsack said that the rules forbid him from being introduced as President Obama’s agriculture chief.

“It eliminates any capacity that I would have to raise resources. I can’t ask anybody for money, I haven’t and I won’t,” he said. “It doesn’t limit your appearance. It just limits how you appear, how you are characterized, when you appear and what you can say.”

Vilsack would not comment on the state of his wife’s race against King, referring questions to her campaign.