Speaking in front of an American flag held aloft by two Caterpillar backhoes at the Warren County Fairgrounds, he returned to the sort of programming that has become a fixture of these campaign rallies. By channeling his own popularity among core party supporters, he hopes to help candidates who need that kind of base to succeed in the midterm elections.

He regaled the crowd with a list of his accomplishments: the confirmation of Justice Brett M. Kavanaugh to the Supreme Court; the release of an American pastor, Andrew Brunson, from a Turkish prison; and newly renegotiated trade deals.

“We are now the hottest country anywhere in the world,” Mr. Trump proclaimed.

He assured attendees that, if Republicans maintained control of Congress, more success would follow: the creation of a sixth military branch, the space force; additional jobs; and completion of a border wall. (The wall has yet to be fully funded.)

Blessings were bestowed — by Mr. Trump and a few state candidates — on the country, the people in Florida and Georgia who have been affected by Hurricane Michael, and Kanye West. (“What he did yesterday,” Mr. Trump said in reference to Mr. West’s Oval Office visit, “was pretty amazing.”)

Vitriol was flung at the news media as Mr. Trump reminisced about his presidential victory and complained about unfair coverage. And admiration was showered upon, among others, law enforcement, Justice Kavanaugh and Justice Clarence Thomas, who similarly faced a bitter confirmation process after being accused of sexual harassment.

He slung barbs at some of his favorite Democratic opponents: Senators Richard Blumenthal and Cory Booker; Hillary Clinton, his rival in the 2016 presidential election; and Senator Dianne Feinstein of California, who drew chants of “Lock her up” from the crowd as Mr. Trump criticized her for what he views as a crucial role in Justice Kavanaugh’s bruising confirmation battle.

“It’s not rule of the law, it’s rule of the mob,” Mr. Trump said, again using the opposition to the justice as a reason that his supporters should ensure that the Democrats not obtain control of either chamber.