A peace hastily formed on the basis of a marriage between Blanche and Louis is just as hastily demolished by the influence of the church. John's indifference to the messenger from the pope is not echoed in Philip, who has to decide whether he will break his second bond of allegiance in the play. John says little and Philip even less while a host of nobles urge him one way or the other, but only the threat of excommunication scares Philip into breaking with John. The conflict between English royalty and the Catholic powers of Rome was an extremely charged issue during Shakespeare's day, the early years of Henry VIII's and Elizabeth I's break with the pope. Including this section in King John offered Shakespeare the opportunity to comment forcefully on the conflict; anyone in a Shakespearean audience would be aware that John's plight was applicable to that of their own age.
John's arrangements with the church are of a far less obedient nature than Philip's. John later demands that the wealth of the monasteries be seized to pay for the war, an act he justifies through his belief that the church is corrupt anyway. But Philip doesn't comprehend that the only power the church has against John is the power to persuade Philip to fight John. And with the urging of Pandolf, he abandons his newest bond with England to support the church.
A peace is broken, and another family is shattered--Blanche, a character who never reappears, is left dangling between two nations on her wedding day.