'This Week' Transcript: Rep. Barney Frank and Rep. Marsha Blackburn

NEW YORK, May 13, 2012— -- (BEGIN VIDEO CLIP)

STEPHANOPOULOS (voice-over): Good morning, and welcome to "This Week."

Making history.

OBAMA: For me personally, I think same-sex couples should be able to get married.

STEPHANOPOULOS: The president embraces gay marriage.

OBAMA: When I meet gay and lesbian couples, it just has tipped the scales in that direction.

STEPHANOPOULOS: Why did he shift now? And what will it mean come November?

ROMNEY: Marriage is a relationship between a man and a woman.

STEPHANOPOULOS: That debate this morning with our exclusive headliners from the House, Democrat Barney Frank and Republican Marsha Blackburn. Plus...

ROMNEY: I did some stupid things when I was in high school.

STEPHANOPOULOS: ... Romney's high school pranks, Obama's college girlfriends making headlines today, but how much should it matter?

America's biggest bank suffers a massive loss. Did JPMorgan fail to learn from the financial crisis?

And on this Mother's Day, the Time magazine cover that has everyone talking. All of that and the rest of the week's politics on our powerhouse roundtable, with Mary Matalin, Hilary Rosen, Ralph Reed, Eliot Spitzer, and Maggie Haberman.

ANNOUNCER: From ABC News, "This Week" with George Stephanopoulos. It's your voice, your vote. Reporting from ABC News election headquarters, George Stephanopoulos.

(END VIDEO CLIP)

STEPHANOPOULOS: Good morning, and happy Mother's Day to all the moms watching. Well, it wasn't the rollout that President Obama had planned, but he did make headlines and history in that exclusive interview with Robin Roberts this week, becoming the first American president to endorse same-sex marriage.

The initial political fallout was surprisingly muted, but strategists on both sides of the issue say it's still too early to tell exactly how it will play in this year's presidential race. Yesterday at Liberty University, Mitt Romney received a rousing ovation for his position.

(BEGIN VIDEO CLIP)

ROMNEY: As fundamental as these principles are, they may become topics of democratic debate from time to time. So it is today with the enduring institution of marriage. Marriage is a relationship between one man and one woman.

(APPLAUSE)

(END VIDEO CLIP)

STEPHANOPOULOS: Let's dig into that debate now with Congressman Barney Frank, the first openly gay member of Congress, and Representative Marsha Blackburn of Tennessee. Welcome to you both.

BLACKBURN: Thank you.

STEPHANOPOULOS: And, Congresswoman Blackburn, happy Mother's Day to you.

BLACKBURN: Thank you so much.

STEPHANOPOULOS: You're welcome. And, Congressman, congratulations to you, as well. You will be marrying your partner in July. Did you expect, Congressman Frank, to have President Obama's endorsement by then? And what do you say to Democrats who worry this is going to cost him votes in a very close presidential race?

FRANK: I expected the president to be supporting same-sex marriage, because, frankly, of the absence of any good reason against it, once you believe that people ought to be treated fairly. The big step forward was when the president said, correctly, earlier this year that the Defense of Marriage Act provision that said, when a state recognizes marriages, the federal government will discriminate and -- and refuse benefits to some of the married people that the state recognizes and not others. That was the major federal policy. Once he said that was unconstitutional, I think the -- the next step followed logically.