Weller was elected as a member of the United States Greenback Party to the Forty-eighth Congress (March 4, 1883-March 3, 1885) but was an unsuccessful candidate for reelection to the Forty-ninth Congress in 1884. After leaving Congress, he was the proprietor and editor of the Farmers’ Advocate, a weekly paper in Independence, Iowa.
Weller served as a delegate to the People’s Party national committee, 1890-1914 and served as president of the Chosen Farmers of America. He was twice an unsuccessful candidate for judge of the Supreme Court of Iowa. He was also an unsuccessful candidate of the People’s Party for Governor of Iowa in 1901. He died on March 2, 1914 in Minneapolis, Minnesota and was buried in Greenwood Cemetery, near Nashua, in Chickasaw County, Iowa.