Blackmail
Blackmail is a major theme in the film, and it is what mobilizes much of the conflict and action. From the start, Sidney Kidd uses the controversial story he has about Seth Lord as leverage to get the Lords to let the journalists into their home. Dexter helps Mike and Liz gain entrance to Tracy's wedding on the condition that Sidney won't run the story of Seth Lord's affair. As a counter to Sidney's blackmail, Dexter gets Mike and Liz to spill some lurid stories about their boss, so that Dexter can in turn blackmail Sidney Kidd.
Divorce
The film starts with a wordless scene in which we see Tracy sending Dexter out of the house. She breaks his golf clubs and he pushes her to the ground in a comically slapstick way. This montage is meant to illustrate a messy and bad divorce, thus communicating to the viewer that, at the start of the film, Tracy and Dexter are ex-spouses. Tracy divorced Dexter because of his heavy drinking, of which she disapproved, and she plans to marry George Kittredge, the absolute antithesis of Dexter, as a way of adding insult to injury. The theme of divorce is not explored too explicitly, but Dexter and Tracy's status as ex-spouses lends their early scenes particular kinds of intimacy and vitriol, in equal measure.
A Goddess in an Ivory Tower
From the start Tracy is depicted as a woman of great strength, independence, and security. Accustomed to wealth and privilege, Tracy is used to getting what she wants in life and does not suffer fools. When he visits the Lord estate on the weekend of Tracy's wedding, Dexter tells Tracy that she is cold, with no trace of understanding for human frailty, comparing her to some kind of impenetrable and hard-to-please goddess. She is hurt by his blunt assessment of her personality, and soon enough her father makes a similar assessment, suggesting that she is made of bronze. When she goes to her fiancee George for comfort, he compares her to a goddess in an ivory tower, a characterization that disturbs her in light of her ex-husband and father's criticism. Despite her strength of character, Tracy wants to be loved and treated like a human being. She wants to be flesh and blood, not bronze. By the end, having dropped some of her harder edges, Tracy triumphantly tells her father that she suddenly feels "like a human being," and he tells her he is proud of her.
Love
While much of the plot of The Philadelphia Story revolves around a wedding, there is not too much talk of love—that is, until Dexter gives Tracy her wedding present. It's a model of a yacht that he and she used to sail around following their wedding called—simply enough—The True Love. When she first receives the model of it, Tracy is nonplused, and only remembers the heartbreak of their marriage. By the end of the movie, however, Tracy recalls the love she once felt for Dexter, and realizes what a mistake they made in getting a divorce. George Kittredge, although doting, was never the man for Tracy, and she decides to forgo marrying him in favor of rekindling the old flame she had with her ex-husband Dexter.
Wealth & Privilege
Wealth and privilege are major themes in the film. Tracy Lord comes from a blue blood, "old money" Philadelphia family, and their giant estate, complete with pools and horses and grand halls, is representative of their massive fortune. Their family has been in Philadelphia for years, in contrast to George Kittredge, who belongs to a nouveau riche class of people who only recently came into their wealth through work. Dexter also comes from the old money class of which Tracy is a part, and they share certain graces and casual attitudes about their privileges that cannot be taught. In contrast to Dexter and Tracy are Liz and Mike, both of whom have no inherited wealth and so must forgo their artistic passions to work at a rather tasteless tabloid magazine. Mike maintains a reverse snobbery towards Tracy and her social set, and he finds their patrician ways and attitudes pretentious and distasteful. When he mocks the highfalutin attitudes of the upper classes, Tracy suggests that classes of people are made up of individuals, and that good people and bad people exist in all classes. After they share an innocently romantic evening and after Tracy softens her attitude a bit, and Mike begins to see that Tracy is a decent person, Mike becomes more forgiving of the upper classes. The same cannot be said for George, who rails against the upper classes after Tracy rejects his offer to get married and forget her indiscretion with Mike.
"Yar"
Part of Tracy and Dexter's shared love of sailing is their memory of what a wonderfully responsive boat The True Love was. "My, she was yar..." says Tracy, referring to the ease of their sails together. "Yar" means that a boat can be easily controlled and manipulated to move with the wind. Later, when Dexter proposes, Tracy promises to "be yar," communicating to him that she is ready to be more suggestible and forgiving as his wife. The notion of a wife being obedient and flexible is at the center of the film. Thus we see Tracy's psychological and emotional journey in the film, from abrasive to pliable, or, "yar."
Tolerance
Another component of what constitutes being "yar" is the notion that people should be more tolerant. Among the complaints leveled at Tracy by various male characters in the film is her father's suggestion that she is too intolerant and unforgiving. When he returns home, she wants to confront him about his infidelity to her mother—which to a modern viewer, seems like an exceedingly reasonable desire—but he insists that since Mrs. Lord has accepted him back without question, Tracy would do well to do the same, and ought to be more forgiving. By the end of the film, she forgives him and displays a more tolerant attitude. To the upper-class WASP-y set that makes up The Philadelphia Story, even through hardship and heartbreak, tolerance is perhaps the greatest virtue.
