Richard Wirthlin has a reputation among pollsters and political consultants as a shrewd adviser. Memos he wrote to Ronald Reagan during the 1980 campaign help explain why.

Elizabeth Drew published the memos in her book, "Portrait of an Election." They show Wirthlin persistently advising that Reagan stick to presidential themes to exploit Jimmy Carter's weaknesses. Others in the campaign credit Wirthlin with keeping Reagan on the offensive and avoiding the direct personal attacks on Carter that some aides advised.

The Wirthlin memos do not mince words. An example: "Survey research conducted in the primary states shows that Ronald Reagan won not because his ideological positions were congruent with the electorate, but rather in spite of a rather substantial ideological gap between himself and the average Republican. The extent of the gap was remarkable..."

The memos also put Wirthlin squarely in the new politics of issue and image manipulation.

"....Events during this period Aug. 17-25 must be consistent with our major theme and strongly reinforce it visually. Most Americans (60%) see the news on TV, they don't hear it or read about it.

"Some suggestions: a visit to a closed defense plant, or shipyard, etc. Care must be taken to assure that the site being dramatized represents what we want it to--an unnecessary cutback."

Wirthlin also made proposals for Reagan's speech of Aug. 18 to a convention of the Veterans of Foreign Wars:

"Remember, our audience is not veterans; it is the 45 million Americans who will hear pieces of the speech, and more precisely our key audience are those 19 million American voters who now say that Ronald Reagan (not Carter or Rep. John Anderson) is best described by the phrase, 'Is a dangerous person to have in the White House' and the 29 million voters who pick Reagan from the triad as 'most likely to start an unnecessary war.' "

Reagan took Wirthlin's advice, making a speech intended to depict him as a man of peace, willing to negotiate arms control with the Russians. But--to Wirthlin's anguished surprise, according to informed sources--Reagan personally wrote in a reference to the Vietnam war as "a noble cause." The media pounced on that and turned the speech into a political negative for Reagan.