As New Hampshire lawmakers gear up for a vote to repeal the state’s same-sex marriage law, state Rep. Seth Cohn (R) is warning the effort could hurt Republicans hoping to hold power after the 2012 elections.Should state lawmakers succeed in reversing the decision, New Hampshire would become the first example of a state legislature overturning its own law on same-sex marriage.“They want this as an election issue,” Cohn said of state Democrats.