U.S. Senator Joe Donnelly of Indiana is one of eight Democrats being encouraged to support gay marriage in a petition being touted by MoveOn.org.
The activist group points out the "last eight" have yet to come out in support the marriage equality for all couples.
Earlier this week, Democratic Senator Bob Casey of Pennsylvania announced his support for gay marriage "after much deliberation."
MoveOn is circulating a number of petitions targeting Democratic senators from Arkansas, Florida, West Virginia, South Dakota, North Dakota, Louisiana and Delaware over the issue.
"Fifty-four percent of Hoosiers oppose a ban on gay marriage," says Indiana MoveOn member Edward Cherlin, who started the Donnelly petition. "We need you to stand up publicly to the bullies and bigots along with the majority of Hoosiers in support of our friends, neighbors, co-workers, and families."