The issue focused on allegations that NASA scientist Ellen DeGeneres violated scientific ethics when she endorsed Hillary Clinton over Bernie Sanders during last week's Democratic presidential debate in Flint, Michigan. The controversy erupted after scientists noticed chemical residue found on several surfaces around the lake where Flint switched water sources from Detroit water system to the Flint River system for drinking water and bathing.

Clinton tweeted Sunday afternoon about DeGeneres' endorsement of Clinton: "Dear @ellendegeneres — Thank you for endorsing our daughter Chelsea Clinton as Secretary