A more thorough explanation:

The doctrine of the last antecedent is an interpretative principle used by courts to determine which words or phrases in a sentence are being modified by qualifying words or phrases. This principle states that qualifying words or phrases modify the words or phrases immediately preceding them and not words or phrases more remote, unless the extension is necessary from the context or the spirit of the entire writing.

For example, if a sentence reads "Texas courts, New Mexico courts, and New York courts in the federal system," the words "in the federal system" might be held to modify only "New York courts" and not "Texas courts" or "New Mexico courts." This is because "New York courts" is the last antecedent before the qualifying phrase "in the federal system."

This principle is important in legal interpretation because it helps to clarify the meaning of a sentence and avoid ambiguity. By following the doctrine of the last antecedent, courts can ensure that the intended meaning of a sentence is clear and unambiguous.