Transcript for Beto O'Rourke fights to unseat Sen. Ted Cruz in Texas midterm battle

That information appeared in dozens of reports in buzzfeed media. Next tonight, the countdown to the midterm elections. Democrat Beto O'rourke fighting to unseat Ted Cruz. The two facing off in a heated debate overnight. O'rourke using a nickname for Cruz first used by president trump. Here's Mary Bruce. Reporter: It's a feisty flashpoint in one of the most closely watched senate races of the year. We welcome the two candidates running for the United States in Texas. Reporter: Democrat congressman Beto O'rourke taking on Republican senator Ted Cruz, with the words of president trump. In the case of lyin' Ted Cruz, lyin Ted. Oh, he lies. You know Ted. He brings the bible, holds it high, puts it down, lies. Ted Cruz is for Ted Cruz. He's dishonest. It's why the president called him "Lyin' Ted," and it's why the nickname stuck, because it's true. Reporter: Cruz is leading in the polls, but O'rourke is hauling in the cash. A staggering $38 million in just three months. He's cultivated a nice guy image in these behind the scenes iPhone campaign videos. O'rourke skateboarding and air drumming through the drive through. But now, as he sharpens his attacks, Cruz is changing his tone, too. The conservative firebrand now calling for Americans to come together. There is a loss of civility. There is an anger. There is a rage on the far-left that is really frightening. You know, the images -- hold on, let me answer. Don't interrupt me, Jason. The images of -- Whoa. A left-wing mob beating on the doors of the supreme court. That's not good for our country. We can disagree while treating each other with respect, while treating each other with civility. This senate race making major headlines across the country. Mary Bruce here in New York. Great to have you here in person. The president first coined the phrase lyin Ted during the presidential campaign, but now it's the democratic and using that same teshg nothing. Reporter: Yeah, and president trump says that O'rourke isn't in the same league as Ted Cruz. And now the president, who once so fiercely attacked Cruz, will be out campaigning for him on Monday. And no longer calling him lyin Ted. Mary, good to have you here in

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