Found corroborating information for Clinton's service and died during WWI - it is in his brother Benjamin's obituary..."Clinton, who died in W.W.I"

Clinton is listed as a Fallen Hero in the August 28, 1919, Manning Monitor WWI homecoming issue.
He is listed with seven other Manning names who lost their lives during WWI.

Clinton, along with Harry Corbin, are not listed in the Manning Centennial book of fallen Veterans.

He is buried in Maple Grove Cemetery, Audubon, Iowa

Apparently Clinton died at the base hospital at Camp Dodge on October 16, 1918.
His father was Orrin Scott Welch who was married twice.
Louisa Bell Arnold was Orrin's second wife and the mother of Clinton.
His WWI registration card shows him living in Manning at the time.
He was born October 22, 1892, in Gray.