With the nation facing huge deficits, Mondale told the voters that a raise in taxes was inevitable. "Mr. Reagan will raise taxes, and so will I," he said. "He won't tell you, I just did." It was a disastrous strategy. Reagan promised prosperity, a strong defense, and balanced budgets without raising taxes. On election day, he lost forty-nine states and carried only MN and DC. Assessing the results, Mondale commented, "Reagan was promising them 'morning in America,' and I was promising a root canal."
http://ontheissues.org/Economic/Walter_Mondale_Tax_Reform.htm
According to almost all independent observers, Mondale clearly won the first debate. Reagan made many mistakes during the debate: he claimed responsibility for creating laws during his time as California's Governor, which were in fact his Democratic predecessor's legacy; he claimed that a large portion of his military budget was for "food and wardrobe"; and he lost himself many times during his speeches. The debate ended with Reagan's closing statement, which, before it began, Reagan declared "I'm all confused now" (Slansky 1989: 112). Reagan's closing statement ends:
MODERATOR: Mr. President, I'm obliged to cut you off there under the
rules of the debate. I'm sorry.
REAGAN: All right, I was just going to -
MODERATOR: Perhaps I should point out that the rules under which I
did that were agreed upon by the two campaigns.
REAGAN: I know, yes (Blume 1985: 332).
However, he failed to transform victory in the debate, which in the past would have been quite a significant achievement, into a tangible boost.
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This runs to the heart of Mondale's campaign. His analysis of Reagan's success was completely wrong. Mondale knew that opinion polls showed that Americans disagreed with Reagan's policies when presented with them directly (Croteau and Hoynes 1994). Thus, he decided to base his campaign around these issues. What he utterly failed to realize is that in spite of the rejection of Reagan's policies, Americans overwhelmingly approved of Reagan the President.
http://it.stlawu.edu/~quack/seminar/mondale_campaign.htm
Now we have some candidates who are again proposing to run for President on a platform that tells the American middle-class: "I will raise your taxes". Is this really the message we want to run on at time when the stakes are so high, and the likely margin of victory in the Electoral College so narrow? I am optimistic that we can take the White House but that optimism is tempered by the political reality that it probably will be a very close election. And one that we can not afford to lose.
Mondale lost in a landslide, winning only his home state of Minnesota and the District of Columbia.