Grant Earl Mouser (September 11, 1868 – May 6, 1949) was a U.S. Representative from Ohio for two terms from 1905 to 1909.

He was the father of Grant E. Mouser Jr., who also became a United States Congressman from Ohio.

Britton was unable to provide any concrete evidence, and was shaken by the vicious personal attacks made by Mouser, which cost her the case.

Carl Sferrazza Anthony, author of Florence Harding, a biography of Harding's wife, wrote that court transcripts in Toledo, Ohio, show that Mouser referred to Britton as a "degenerate and pervert", and "brought (Florence Kling Harding) in by using Warren's 'love of his good wife' against a 'distorted... deranged... demented... [and] diabolical' Nan who had no respect for the marriage tie...."[citation needed] DNA testing in 2015 confirmed that Blaesing was indeed Harding's daughter.

This article incorporates public domain material from the Biographical Directory of the United States Congress