President Obama is speaking out in favor of same-sex marriage, a move fellow Democrat and Iowa Senator Tom Harkin says is “the right thing, the courageous thing.” It follows Tuesday’s vote that made North Carolina the 30th state to pass a constitutional amendment defining marriage as only being between a man and a woman.

Harkin says his personal views on gay marriage have changed during his time in Washington. “My thinking on this has evolved over the years, too,” Harkin says. “All of us have (evolved), as we get a better concept of civil rights and expanding equality under the Constitution of the United States, all of us, many of us, our thoughts have evolved, mine along with it.”

Iowa is among six states and the District of Columbia that allow same-sex marriage. Harkin says he’s done a one-80 on this subject in the past 15 years. “I’m a co-sponsor of the bill which is the Respect for Marriage Act, which would repeal DOMA, the Defense of Marriage Act, which, in all frankness, I will say that I voted for back in the ’90s. I think now we recognize, at least I recognize, that this is not correct.”

DOMA, enacted in 1996, is a federal law that defines marriage as the legal union of one man and one woman. Harkin says voters in North Carolina and elsewhere likely haven’t heard the last of this issue. “If you’d left it up to North Carolina and South Carolina and Alabama and Mississippi back in the ’60s, they would’ve amended their constitutions to deny civil rights to African-Americans,” Harkin says.

“I have no doubt about it. But, that wouldn’t have held up under the Constitution of the United States.” While some analysts say gay marriage will be a key issue in the fall election, Harkin disagrees, saying the real focus will be on the economy.