drag sb's name through the mud

drag sb's name through the mire/mud (to damage someone's reputation by saying extremely insulting things about them) — запятнать чье-л. имя, репутацию; запачкать чье-л. имя, репутацию; вывалять в грязи (перен.)

Example: It WAS a tragic accident. We all loved Diana and history will recall how her counrty dragged her name through the mud for so many years after her passing.

See also
[поливать грязью]
[badmouth sb ]