In a fiery speech defending Moore, Bannon attacked the Republican establishment and questioned the timing of allegations brought against Moore by eight women who have accused him of sexual misconduct or inappropriate behavior toward them when he was in his 30s and, in some cases, the women were in their teens. Moore has denied the allegations.
"Let's be right, ok, this whole thing was a setup, this whole thing was weaponized, right?" Bannon said of the allegations of sexual misconduct first published by the Washington Post, "You know that, folks down here in Alabama know that."
"Hey Flake this is why your approval rating in your home state is like 11 percent," Bannon said, "You're a total embarrassment, if you're going to write a check write a check, support somebody."
"Judge Moore served his country in one of the toughest wars we've ever had, Vietnam," Bannon said, "Mitt, that's honor and integrity, and by the way Mitt, while we're on the subject of Vietnam and honor and integrity, you avoided service brother. Ok Mitt, here's how it is brother, the college deferments that's we can debate that, but you hid behind your religion. You went to France to be a missionary while guys were dying in rice patties in Vietnam. Do not talk to me about honor and integrity."
Moore did not directly address the allegations against him, but did talk about the "battles" he has fought in the campaign.
"If you knew what kind of battles I've been fighting, you wouldn't want to be where I am. In fact if I wasn't here I wouldn't want to fight these battles, but when God puts you there, you have nothing else to do but to stand," Moore said.
Moore again cast the race as a chance for Alabama voters to reject the "establishment" and said the race was special because it is the first senate race since the election of President Trump.
Moore sounded confident in his chances of victory on December 12.
"I think they're afraid that I'm going to take Alabama values to Washington," he said. "And I want to tell you, I can't wait."
Bannon's trip to the state comes at a crucial time in the campaign, and just a day after Trump officially endorsed Moore, calling the candidate personally and expressing "enthusiastic support" for Moore, according to a statement from the campaign.
Speaking today at the White House, Trump reiterated his support for Moore.
Most Republican senators have continued to keep their distance from Moore. McConnell told reporters today that he has not changed his position that Moore should get out of the race, and said that if elected, Moore may still face an ethics committee investigation.
"There's been no change of heart," McConnell said. "I had hoped earlier he would withdraw as a candidate. That obviously is not going to happen. If he were to be elected, he would immediately have an ethics committee case and the committee would take a look at the situation and give us advice."
Other Republican senators have expressed their displeasure with Moore, but said the decision on whether or not he should be a U.S. senator is up to Alabama voters.
ABC News' Ali Rogin contributed to this report