How was the ""one-drop rule"" related to laws forbidding miscegenation in the united states?

It was never a federal law

Explanation:

Is a social and legal principle of racial classification, associated with the principle of "invisible blackness" that developed after the long history of racial interaction in the South.

Miscegenation laws banned black people and non-white groups from marrying white people.

"one-drop" rule, which often signified racial delineation by any non-white linage, was eventually formalized by law.