P designs, markets, and distributes apparel, home furnishings, fragrances, and accessories under the name Ralph Lauren. It frequently employs as a trademark the polo player symbol, which has appeared on Ralph Lauren clothing since 1972. D, founded in 1890, is the governing body of the sport of polo in the United States. P obtained a judgment in 1984 enjoining D from the use of certain marks that infringed P's trademarks. The judgment made clear that D remained free to 'conduct a retail licensing program utilizing . . . a mounted polo player or equestrian or equine symbol which is distinctive from the [Ralph Lauren] polo player symbol . . . .' P brought this action against D and its licensee, Jordache, Ltd., alleging that logos used by the Ds on a clothing line violated their trademarks. In September 2003, after three years of pre-trial litigation, the parties settled a number of their disputes. The settlement agreement left unresolved whether D’s four double horsemen marks infringed P's trademarks. The parties stipulated in the settlement agreement that this claim would be resolved by a jury trial. The four disputed marks include: (1) a solid silhouette of the two horsemen, (2) the same solid silhouette with the letters 'USPA' added underneath, (3) an outline of the two horsemen, and (4) the same outline with 'USPA' added underneath. D defended claiming that P had acquiesced to D’s use of the logos and relied to the tune of $41 million to promote the new logos. The court allowed D to present evidence of discussions at settlement negotiations between P and D. Jenkins, a USPA employee, testified that P had consented during settlement negotiations to D's using a certain version of the logo. P objected on the ground that the testimony was prohibited under Rule 408. D got the verdict in its favor on 3 of 4 logos, and P appealed.