1. In a 2- to 3-quart pan, combine wine, 1 cup water, sugar, and lemon juice. Boil over high heat, stirring occasionally, until reduced to 1 1/4 cups, 10 to 15 minutes.
2. Remove from heat and stir in liqueur, vanilla, berries, and cantaloupe.
3. Nest pan in a bowl of ice and stir often until cool, about 10 minutes.
4. Ladle soup into bowls.