This week, ghosts from the past came back to haunt some of the biggest potential 2016 candidates. Here's ABC's senior Washington correspondent Jeff Zeleny. Reporter: Four 2016 hopefuls. Four obstacles... See More
This week, ghosts from the past came back to haunt some of the biggest potential 2016 candidates. Here's ABC's senior Washington correspondent Jeff Zeleny. Reporter: Four 2016 hopefuls. Four obstacles to overcome. For Hillary Clinton, an old audio recording this week that went viral. From her time as a young Arkansas lawyer. She defended a rape suspect. She explained how she helped him get a light sentence, even though it seemed she believed he was guilty. He took a lie detector test. I had him take a polygraph, which he passed. Which forever destroyed my faith in polygraphs. Reporter: Fresh fodder after the 12-year-old rape victim who is mow 52 criticized Hillary Clinton. Hillary Clinton took me through hell she told a newspaper. For Wisconsin governor Scott walker. A more recent case. Documents unsealed this week show prosecutors were trying to prove he was at the center of an illegal fund-raising scheme at the heart of his 2012 election. He says the claims are politically motivated. The media jumps on this. You get a spin on this. Some detractors trying to claim there is more than there is. Reporter: And for Chris Christie, bridge gate still seems to hang over everything. Everyone at this gathering of conservatives Friday. I'm called lots of different names. But indirect has never been one of them. Reporter: Then, governor Rick Perry. Dogged by his own words. This time, comparing homosexuals to alcoholics. I may have the genetic coding that I'm inclined to be an alcoholic. But I have the desire not to do that. I look at the homosexual issue as the same way. Reporter: He stopped short of an apology. But backpedalled this week. I readily admit I stepped right in it. Reporter: For Clinton, walker, Christie, Perry, and all potential candidates, how they contend with the ghosts from their past is a critical part of the road map for their future. Thanks to Jeff. Now back with the "Roundtable." Greta, you interviewed Hillary Clinton. How has it gone? First of all, the whole thing about the rape victim. I think some of the lousiest reporting I have Ian in a listening time. Scott walker in Wisconsin, a republican. And Hillary Clinton, democrat. Because what she wrote in this affidavit wasn't her feelings. She said she was told this. Totally routine. Like wise, Scott walker. The headline says he's accused of a crime by a prosecute person that's what prosecutors do. They accuse you of a crime. If they thought he committed one, they would have charged him. You have lazy reporters who don't look at the court file for Hillary Clinton and lazy reporters who don't understand the system in Wisconsin. Hearing the tape and hearing Hillary Clinton laughing about how the guy was -- she believed the guy was guilty. No question that that will be politically damaging. For the people that don't like her already. We're such a polarized society right now. The person you like could have done something horrible, you're still going to like them. There's not much in the middle. That said, she was clearly zealously defending her client. That is what she's ethically obligated to do as a lawyer. Absolutely. The people who call themselves constitutional conservatives. The sixth amendment says you have the right to counsel and that counsel must fight for your interests. If you don't like that, take it up with Thomas Jefferson. There is a judge, a prosecutor, a jury. Your job as a defense attorney is to go after it. She wasn't laughing at the victim. She was laughing at the polygraph. That is very different. That's why the reporting was so sloppy about her and Scott walker, too. And polygraphs are a joke. We're going to have plenty of time to debate the 2016 election. She had a terrible rollout on the book. I'm hearing it's just dropped. And the sales. But I don't think something -- They're claiming they're doing fine. I don't think something she did when she was 27. At the end of the day, look, we've all changed. I'm only 36. I was totally different at 27. I don't think this will be a big damaging thing. There will be a lot of things on both sides to run on and have a spirited debate. I want to turn to one of the other big stories this week. The irs. A very contentious hearing with the irs commissioner. About the missing e-mails. Listen to Paul Ryan. I am sitting here listening to this testimony. I just -- I don't believe it. That's your problem. Nobody believes you. You ask taxpayers to hang on to seven years of their personal tax information in case they're audited and you can't keep six months' worth of employee e-mails? It looks horrible for the irs. Let me ask you the reverse. Do you really think that somebody at the irs intentionally destroyed six months of e-mails to cover up something? Do you believe it's a coverup that big? Based on the time line, no. Apparently the complaint was made before there was an investigation. However, I certainly think there is -- I Doan think it is a phony scandal like the president does. Neither does secretary Hillary Clinton think it's phony. I think it's terrible that it's dragging out this long. And that the irs tells the committee in February that the e-mails will be produced, it takes two years, they don't exist. They know about it. I thing -- think there's a lot of smoke there. Do I think someone deliberately did it ahead of time? I don't think anyone is that smart or clairvoyant. That's the implication by Paul Ryan here. Right. There is zero trust across the partisan line. The idea that it is far fetched will not be accepted as a legitimate explanation by half of the country. It would be the same if the situation were reversed. I don't think this is just about a lack of trust. It is about a real issue. The irs, supposed to be the most independent organization, coming after tea party conservative groups, in essence, by their own admission, and then finding out, oh, goodness, we lost these e-mails. Maybe there was no scandal. But we have to get to the bottom of it. It's not a partisan issue ads much as it is a reality. There is no scandal here. This is about distraction. Just like the whole benghazi thing. They don't want to talk about -- Let me ask you. Aren't you concerned about six months' worth of e-mails? There is an e-mail where she said my computer crashed. It doesn't time out right. This is about distraction. Refusing to extend -- raise unemployment -- the minimum wage. I think you underestimate. We'll pick it up next week. Thank you very much.
This transcript has been automatically generated and may not be 100% accurate.