Transcript for Bannon breaks with Trump in Alabama Senate race
President trump facing a test at the polls and the president is pushing for Luther strange. He is facing a strong Republican primary challenger, and that person is backed by Steve ban. ABC's chief national correspondent, Tom llamas, is in mobile. For whatever reason, god has put me in this election -- Reporter: Overnight, former Alabama chief justice, Roy Moore, making it clear, he is going to defend the second amendment. I believe in the seconded amendment. Reporter: And this morning, political trouble could be coming for president trump on horseback. Moore will ride to the polls to vote for himself in the senate Republican primary. I Ron the last time I rode a horse. Reporter: He is facing Luther strange who is backed by president trump. They want to see what the people of Alabama do tomorrow. Reporter: Moore has won over some of the trump's most prominent supporters, including the president's former chief strategy strategist, Steve Bannon, who is breaking with the president in this race. We did not come here to defy Donald Trump. We came to praise and honor him. Reporter: Who should they vote for? I came down here for judge Roy Moore. Reporter: But the president is sticking by Luther strange. I say, setor, I need your help. I said, I got to get your vote on health care. He says, you have got it. Reporter: Senator strange was appointed to Jeff sessions' seat when sessions was confirmed as attorney general. He is the tallest person to serve in the senate. I said, that is the tallest person I have ever seen. That's why I call him big Luther. Reporter: But he is facing a big challenge in Moore who is well known by conservatives for refusing a federal order to remove a ten commandments monument from a judicial building, and later suspended as a judge for ignoring the supreme court ruling on legalizing same-sex marriage. Strange who campaigned with Mike pence overnight is banking on that white house support to deliver victory. The vice president and the president of the United States, came here on my behalf, and it means more than I can possibly say. Reporter: Now strange and his supporters which include a superpac linked to senator Mitch Mcconnell have poured millions into attack ads in this race, but local reports show Moore on top, and president trump tweeted this morning saying, Luther strange has been shooting up in the Alabama poll since my endorsement. Finish the job. Vote today for big Luther. Robin? We'll see what happens. All right, Tom.
This transcript has been automatically generated and may not be 100% accurate.