In a contentious exchange over the Defense of Marriage Act, McMahon said, "I have changed my position on DOMA because with now gay marriage approved in the state of Connecticut, I don't think it's fair."
Murphy responded that McMahon's waffling "displays how weak her commitment is to standing up to the Republican right wing."
Clarifying afterwards in the post-debate spin room, McMahon told reporters that "I would vote to repeal DOMA... my opinion has just been evolving and I clearly want there to be fairness. And there just isn't fairness, you know, with DOMA."
McMahon's comments mirror President Obama's own - yet pro-gay marriage Democrats consistently withheld the kinds of harsh words for their party's leader that Murphy reserved for McMahon on Sunday.
In October of 2010, Barack Obama said he thinks that "attitudes evolve, including mine." At a White House press conference two months later, Obama said "my feelings about this [gay marriage] are constantly evolving."
McMahon went from opposing gay marriage to supporting it in the same timeframe as President Obama. The Connecticut Senate race has been tight, with polls showing the opponents within three points of each other.
Editors' note: an original version of this story at one mention said that McMahon's opponent in the general election is Chris Shays, not Chris Murphy. Shays was a Republican running against McMahon in the GOP primary; Murphy is a Democrat running against McMahon in the general election. Townhall regrets the error.