Writing in New York magazine during the l988 primary campaign, media experts Edwin Diamond and Stephen Bates, authors of The Spot: The Rise of Political Advertising on Television, pointed out that political advertising for each campaign follows a predictable three-stage cycle. Knowing the stages can help any viewer follow the fortunes of each candidate and avoid being manipulated by slick advertising techniques. Here's what to look for:

1. Bio ads help candidates put their best faces forward. From Dukakis' stress on his immigrant background to spots featuring Robert Dole's Kansas hometown, candidates' introductory campaign ads emphasized their ties to the land and the common person.
   
   
2. Issues, policies and programs appear in the second stage, which helps the candidates demonstrate leadership and distance themselves from the pack. When candidates are in trouble, they're apt to start switching issues.
   
   
3. When candidates trail in the polls, they attack the opposition. The more financially strapped the campaign, the earlier the attacks.