It's the classic explanation of why the political right wins by appealing to voters' emotions, and the left loses by relying on rationality. It's the best explanation for George W Bush. It also explains why Labour fails to win support with statistic-rich documents and fact-heavy speeches. Recently, though, Westen's advice has been taken to heart. Labour is preparing to get emotional.
On Valentine's Day this week we will see Gordon Brown talk candidly on TV about the death of his baby daughter Jennifer, with Piers Morgan. The emotion is raw, the tears real.
Justin Forsyth, an adviser to Brown, watched the interview from the wings and says it will be 'great TV' and 'moving'.
We're used to public figures talking about their private lives. Are we ready for the Prime Minister to show his emotions? The days are gone when Prime Ministers could be emotionally cold. Today, the Iron Lady would need a squidgier side. Attlee's stiff upper lip would have to wobble. Brown may be the 'cleverest man in the room' according to actor David Tennant. But for an electorate weaned on Oprah, Jeremy Kyle and red-top confessionals, 'clever' doesn't cut it; you have to be able to cry.