Republicans trapped in abortion debate

>>> on the campaign trail today, congressman todd akin continued what's being called his apology tour for his remarks about rape and abortion after inflicting unforeseen and great damage on the national party . but there is more to report tonight. nbc's andrea mitchell has that story.

>> reporter: mitt romney in iowa, paul ryan in north carolina . today both zeroing in on the economy. but because of todd akin only days before their convention, republicans remain trapped in a national debate about abortion and rape.

>> it's been an exciting day.

>> the best we can.

>> reporter: on "today," akin told matt lauer he apologized.

>> i apologize. but i don't apologize in the fact i'm strong on pro-life.

>> paul ryan sponsored one bill with akin that could outlaw all abortion even for rape victims. today ryan says he'll follow mitt romney .

>> his policy for rape, incest, the life of the mother, i'm comfortable with it.

>> reporter: romney once supported pro-life. the man that came up with the discredited rape theory. a theory he repeated a few days ago telling "new york times" rape victims are unlikely to get pregnant saying, quote, this is a traumatic thing. shall we say she's uptight, frightened, tight. sperm are less likely to be fertilized. not what mitt romney wants to focus on.

>> romney took pains to go out of his way to make sure he never talked about abortion, whether it be to me or others. he just didn't want to have anything to do with it.

>> reporter: meanwhile claire mccaskill all but counted out before the controversy now has a real chance.

>> i'm going to run against todd akin and draw the contrast necessary so voters know he's outside the mainstream.

>> reporter: if the republicans thought they could escape this issue, the party's platform has adopted an anti-platform with no exception for rape. mitt romney clearly made it clear he disagrees entire with todd akin 's views.

>> andrea mitchell in our newsroom.