Transcript for Michigan Primary: Romney Pushes for Votes
We're about to learn one of the biggest secrets in presidential politics. Are the voters of Michigan going to give Mitt Romney of victory in his home state. And vault him back to the head of the pack. Or is Rick Santorum going to derail him tonight. Our team is on the ground tonight and the trail that began in Iowa. All comes down to this moment and ABC's David -- starts us off from the Romney camp right now David. Diane good evening to you this incredible political probable -- -- right here tonight Mitt Romney's headquarters his. War room just down the hall here and as you know this was supposed to be one of the easier victories Mitt Romney's home state. This campaign acknowledging to -- today -- how crucial this races tonight and saying the stakes are enormous and in a marked difference here in this state. They would not predict to -- who they think will win here tonight. You guys let's get the cause -- -- Republicans out about. At -- headquarters today it all out push for votes you were on the first campaign to help them win. Yes -- headquarters of -- -- has he got when he first campaign for Mitt Romney's father once governor here. But tonight -- will be far more than his roots -- where he was supposed to be homecoming king. Now locked in a bitter battles with Rick Santorum. Governor let me ask you what would you -- -- Republican Party members who say Michigan should never have been this close. And the greater concern that you have yet to excite the Republican base -- -- You know it's it's very easy to excite the base with incendiary comments. We've seen throughout the campaign that if you're willing to say really outrageous things. You know -- I'm not willing to let my hair on fire to -- get support. Santorum is not a legal and after conservative blue collar Republican to fuelled his surge tonight he's going after Democrats to. A controversial -- robo calls urging Democrats to come out -- vote for him to. Michigan they're allowed Romney supported the bailouts were his walls Greek billionaire buddies. But oppose the auto bailout that was a slap in the face to every Michigan workers. What the Santorum called does not mention is that he too opposed the auto -- Tonight the Romney camp calls this phone calls outrageous bunny himself calling it a new low. But Santorum says it didn't bother Romney when he got help from Democrats in New Hampshire. But on this crucial day -- did acknowledge something else some of the missteps and made headlines at his home. You see it made some mistakes I'm curious what you're talking about -- I can't imagine. You have a hard time coming up with the yeah. Never teach your mistakes put -- A little -- -- there in that room the governor was asked of comments like the one where he mentioned his wife having to cadillacs actually hurt him. He answered quite simply yes but that he -- very quickly. Inserted his campaign strategist today Diane saying that Rick Santorum is an economic lightweight they want to shift the conversation back to the economy. And they know what they're up against in the next 24 hours K David nice -- on those mistakes and what about that man causing so much trouble for Romney conservative firebrand Rick Santorum. ABC's Jon Karl spent the day with him John. Diane Rick Santorum has been playing the scrappy underdog here trying to score a knockout blow against Mitt Romney. Here in Michigan that is something it seemed impossible just a few weeks ago but now when you go around the state Santorum clearly seems to be a candidate who has momentum. I caught up with him earlier today at one of his local campaign offices he said he has no idea who's going to win here. But I also asked -- about that comment from Romney that he is an economic lightweight. Romney's calling you an economic -- lightweight. What do you make of that. I think it's sort of funny. Or that that that someone. Would say that I am I in the heavyweight in this race when it comes to -- in this country in the conservative direction. Governor Romney is zero accomplishments -- absolutely. -- Now the Santorum team says that no matter what happens here tonight win or lose they have actually already won here. By forcing Mitt Romney to fight so hard to defend his home to her Diane. Tracking them down today thank you John I want to bring in co anchor of Good Morning America an -- this week George Stephanopoulos you have the first round of exit polling tell us what -- -- -- they show first of all the conservatives are dominating this electorate six out of ten voters are conservative here's why the race is so close Diane. They're split right down the middle between very conservative voters and somewhat conservative voters those -- are going in opposite. Directions also another tidbit one out of ten voters -- they are Democrats who saw Rick Santorum going after -- that's not as many. As a -- in the past Republican primaries but it's enough to make a difference as some Democrats are and there are those injured just certain -- selection makes mr. Kate Georgia and I of course will be standing -- through this evening with the powerhouse political team of ABC. Bringing you the results as they come in through the night and we hope you'll be joining us.
This transcript has been automatically generated and may not be 100% accurate.