I believe that the foolish sense of judgement that both the Prince of Morroco and the Prince of Arragon have, lead them to choose the wrong casket. Portia also played a role in influencing the princes' choices by her manner. How she spoke to them and how she treated them may well have tainted their choices. First, the Prince of Morroco looks over all the inscriptions. After a second looking over, the Prince decides that …showed first 75 words of 711 total…

…showed last 75 words of 711 total…with the other two suitors, Portia seemed cold and uncaring. She didn't care in the least for the Princes and certainly wouldn't bother to help them choose. Her influence on Bassiano through her language and subtle hints surely helped him choose the correct casket. Morraco and Arragon's pure foolishness as well as Portia's disliking played against them and, in keeping with Shakespeare's trends, Bassiano's love for Portia proved true and made them a happy couple.