Summerland, Calif.

POLITICAL mythologies endure. One myth that is enjoying a revival in a year when Republican presidential candidates are comparing themselves to Ronald Reagan, their iconic hero, is the notion that Mr. Reagan defeated President Jimmy Carter in 1980 by a coded appeal to white-supremacist voters.

The core of this myth is the claim that Mr. Reagan scored a political masterstroke when he spoke on Aug. 3, 1980, at the Neshoba County Fair in Mississippi. At the fair, Mr. Reagan told a cheering and mostly white audience, “I believe in states’ rights” and that as president he would do all he could to “restore to states and local governments the power that properly belongs to them.”

He had been talking this way for two decades as part of his pitch that the federal government had become too powerful. What was different this day was not Mr. Reagan’s words but where he said them: Nearby Philadelphia, Miss., was notorious for the murders in 1964 of three civil-rights workers, killed in cold blood with police complicity.

In the wake of Neshoba, Mr. Reagan’s critics pounced. President Carter’s campaign operatives portrayed Mr. Reagan as a divisive racist. At a money-raising event in Chicago, Mr. Carter told his audience: “You’ll determine whether this America will be unified, or, if I lose this election, Americans might be separated black from white, Jew from Christian, North from South, rural from urban.”