Transcript for What's at stake in the 2018 midterm elections

Stakes are high Georgia and elsewhere, so we'll go to Tom llamas for a quick rundown of the stakes tomorrow. What to look for as the night goes on, and what could tip the results one way or another. Good morning, Tom. Reporter: Guys, morning. I'm here at ABC news election headquarters where the results will come in here. Every square inch of this studio built to capture the excitement of what could be a historic night. Behind me we'll have our political team watching the results coming in. Out on the team, a field of correspondents, producers and photographers with the candidates and all the data we're gathering will be broken down with the help of the 3D model of what I'm about to show you. Let's look at what is at stake in this election. All house seats are up for grabs and Democrats need to pick up 23 to take control for the first time in eight years. In the senate, a much different story. The Democrats are on defense. They need to gain two seats, but they could lose even more, and across the country, we will also be keeping a close eye on 36 governors' races. This election could be historic with the potential for massive voter turnout. 80% of registered voters in our new ABC news/ "Washington post" poll saying they are certain to vote or have already voted. That's compared to 65% back to 2014. In our poll, Donald Trump has the lowest approval rating in the midterms since Harry Truman. He is at 53% disapproval. We'll find out what effect the president has on this very shortly. Back to you. Okay, Tom. Thanks very much.

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