As president of the United States, Ronald Reagan wove a rich tapestry of illusions - "It's morning in America!" - that did a lot to obscure the substance of his administration.

Since his death in 2004, the myths have become denser. Comparing him with George W. Bush even created a certain nostalgia for the Reagan years, and by now the reality of his administration has all but vanished from sight and memory

This is unfortunate, because a clear vision of the past is vital for constructing a better future.

In December 1981 about 1,000 civilians, mostly women and children, were massacred by the Salvadoran army at a village called El Mozote. The killers were an elite unit, the Atlacatl Battalion, that had been organized, trained and equipped by the United States.

The Reagan administration denied that any such crime had occurred, and the Atlacatl and its commander continued to be favored by US military advisers in El Salvador.