The economic reality of the nation going over the "fiscal cliff" is already hurting retailers hoping to cash in on Christmas shopping.

Walmart President Mike Duke, speaking to the Council on Foreign Relations Tuesday, suggested that his customers are growing worried about the impact of the huge tax hikes that will kick in if Congress and President Obama can't cut a deal by the end of the year.

According to the Council, Duke said:

"The week before the election, only one-fourth, 25 percent of our core customers even knew what 'fiscal cliff' meant. One week after the election it was up to 75 percent. Now...15 percent of our customers are telling us the conversation on the fiscal cliff will affect their Christmas spending."