Barack Obama, speaking at a Wednesday campaign rally in suburban Atlanta, offered a closing argument for Democrats in the final week of the midterm election campaign.

“These are not serious people,” he said of Donald Trump and the Republican party. “And we’re all paying the price for their lack of seriousness.”

Obama came to Georgia to support the campaigns of US senator Jon Ossoff, former Atlanta mayor and gubernatorial hopeful Keisha Lance Bottoms, and an array of down-ballot Democrats as part of his cross-country campaign tour before next week’s election. From 3,500 to 4,000 people filled the Discovery Center of Clayton county for the late election season stop, just south of Atlanta.

Obama has been casting caltrops behind him with each campaign stop, offering pointed criticism of Republican candidates and Donald Trump that has been unusual for the former president. He continued to do so on Wednesday, again invoking the image of Trump’s gilded renovations of the White House and noting Trump’s strident reaction to his crack last week likening it to Saddam Hussein decorating a Cheesecake Factory.

“The Saddam Hussein thing didn’t bother him. But he was very upset about the Cheesecake Factory,” Obama said. “I mean, it’s all crazy, but this is the crazy part: they mobilized a whole government response to that joke.

“The White House even called the secretary of the treasury,” the former president continued. “The guy who is trying to figure out how to lower inflation … they told him he should hold a press conference in front of the Cheesecake Factory.”

He also rebuffed Republicans’ accusations of snobbery for referencing the popular chain restaurant.

“I am the father of two daughters,” Obama said. “Do you think I could have survived their childhood without going to the Cheesecake Factory?”

But he turned that discussion to the problems of affordability for American voters, in contrast with the corruption of the presidency.

“We have never seen a president so intent on selling favors,” Obama said. “The guy has made billions of dollars while in office. Understand that this has not been done in modern times.”

The construction of a new ballroom on the site of the former East Wing of the White House featured in the comments of many speakers at Wednesday’s rally, including Ossoff.

“Each day, Donald Trump digs the moral pit deeper,” Ossoff said, accusing the president of leading “the most corrupt administration of all time, and everybody knows it”.

“If you’re involved in any of this, next year you’ll be raising your hand to tell the truth, the whole truth and nothing but the truth,” Ossoff said, in reference to Democrats pledging to impeach Trump if they take control of Congress next year.

The crowd chanted: “Lock him up!” in response.

Bottoms, meanwhile, contrasted her candidacy with that of her Republican opponent Rick Jackson, tying the billionaire healthcare executive to Trump and describing them as “two out-of-touch billionaires who want to keep getting rich on the backs of taxpayers”.

Invoking the legacies of US Representative John Lewis and Coretta Scott King, Bottoms characterized her candidacy as transcending politics. “They may have the money, but they will never overtake our movement,” she said.

Despite a broad wave of Democratic support buoying candidates across the country – and the eight- to 10-point polling lead Ossoff has on his Republican opponent, US Representative Mike Collins – Bottoms is statistically tied in polls with Jackson. If elected, Bottoms would break the state’s Republican trifecta – where the GOP has controlled both chambers of the legislature and the governor’s office – which began in 2004.

Rev Raphael Warnock, Georgia’s other senator, warned of “spiritual wickedness in high places” while describing the effects of deep cuts to Medicaid and Snap nutrition support for children.

“This is about the character of the country,” Warnock said. “This is about who we are and whether we are here for one another … I am concerned about the spiritual health of our country. There is brokenness, because only a broken nation could manage to elect Donald Trump twice.”

Trump, who was campaigning in Ohio at the same time as the Georgia rally, has also been on a national rally blitz, holding near-daily events in the final days of the midterm campaign. Trump has made two appearances in as many weeks in Georgia, both in what would otherwise seem to be congressional districts that are safe territory for Republicans.