Race for the white house now. "Your voice, your vote." And there was some hope this weekend that the choice of paul ryan might change the tone of this presidential race. That did not last long. The... See More
Race for the white house now. "Your voice, your vote." And there was some hope this weekend that the choice of paul ryan might change the tone of this presidential race. That did not last long. The president and vice president taking hits for comments they made yesterday. And mitt romney fired back with his most fiery rhetoric yet. Abc's david muir is on the trail in columbus, ohio, with all of the details. Good morning, david. Reporter: Hey, george. Scathing words from mitt romney, aimed directly at the president and the vice president. Vice president biden trying to defend what he said in the last 24 hours. And the president himself, well, he's talking about mitt romney's dog. Not once, not twice, but three times. This is what an angry and desperate presidency looks like. Reporter: Mitt romney came out swinging overnight, bouncing on comments made by vice president joe biden. Biden was criticizing romney's promise to loosen regulations on the big banks in wall street. He's going to let the big banks, once again, write their own rules. Unchain wall street. They're going to put y'all back in chains. Reporter: Romney taking aim at that biden moment and the president's campaign. Wild and reckless accusations that disgrace the office of the presidency. Another outrageous charge just came a few hours ago in virginia. And the white house sinks a little bit lower. Reporter: Vice president biden is now trying to explain the chains remark. Saying republicans, including romney's new running malt, paul ryan, have spoken of -- we'll unshackle our economy. Reporter: He used the word, unchained instead of unshackled. The last time these guys unshackled the economy, to use their term, they put the middle class in shackles. Reporter: There was no apology. The obama campaign called romney's speech last night unhinged. And president obama in iowa, hit on a touchy subject again. While criticizing romney's stance on wind energy, he brought up the story that followed romney about strapping the family dog to the roof of the romneys' car. It was the third time the president brought it up. You can't drive a car with a windmill on it. I mean, maybe he's tried it. He's put other things on the roof. Reporter: Meantime, in las vegas last night, romney's new running mate, paul ryan, met with hundreds of protesters. A sign of just how heated this race has become. Paul ryan will be here in the battleground of ohio today. Michelle obama joining president obama in iowa for the first time this campaign season. George, given the rhetoric of the last 24 hours, we were all wondering out here, what are they going to be saying by labor day. You're exactly right. Thanks very much.
This transcript has been automatically generated and may not be 100% accurate.