The clear statement rule is a type of guideline used by courts for statutory construction. According to this rule, the courts should not interpret a statute in a way that will bring a particular result which was not intended by the statute. If the courts are to interpret the statute to bring a result, it should have been clear from that statute that the result was intended by the text of the statute itself. This rule insists that a particular result can be achieved only if the text says so in certain terms.
For example, Congress can abrogate the states sovereign immunity in some situations. In such case, congress cannot do that simply, it must make the intention unmistakably clear from the language of the statute.