What principle is established by the mailbox rule?

The mailbox rule establishes that acceptance of an offer is valid when the acceptance is sent, rather than when it is received by the offeror. This principle is significant in contract law because it clarifies when and how acceptance occurs, providing a decisive moment that protects the interests of the offeree.

When the offeree sends their acceptance, they are acting within their rights to form a binding agreement, regardless of whether the offeror has received it. This rule offers certainty and encourages prompt communication in negotiations. It benefits the offeree because once the acceptance is mailed, they do not have to worry about whether the offeror has received it to ensure that a contract has been formed.

In contrast, other principles associated with communication, such as requiring delivery of the offer for acceptance or needing explicit rejection, do not apply in this scenario, as those pertain to other dynamics of contractual communication rather than the moment acceptance is considered effective.