What is the theme in The Golden Bowl by Henry James?

In many ways this novel presents marriage as a political affair. While modern Americans generally marry for love and affection, the characters in this novel seem to view marriage as a way either to move up the social ladder or a means of accessing what their mate can provide for them. For instance, when the Prince marries Maggie, one of his thoughts is that he is now associated with, and is in fact, one of the rich. It is suggested, on the other hand, that Maggie marries the Prince because of his historical background. She is, in a way, adding this piece of Italian royalty to her father's collection. When Mr. Verver marries, he chooses a spouse who can be useful to him. Charlotte fills in the gap that Maggie left behind when she married the Prince. One can only guess that Charlotte married Mr. Verver as a way to get close to the Prince again.