In a bullish interview, the White House chief of staff, Ron Klain, compared Joe Biden’s achievements in his first two years in office to historic successes under Franklin Delano Roosevelt, John F Kennedy and Lyndon B Johnson.

Speaking to Politico, Klain said: “The president has delivered the largest economic recovery plan since Roosevelt, the largest infrastructure plan since [Dwight D] Eisenhower, the most judges confirmed since Kennedy, the second-largest healthcare bill since Johnson, and the largest climate change bill in history.”

Klain’s comments, aimed at voters contemplating the midterm elections, are an indication that Democrats plan to campaign heavily on their accomplishments in the less than two years they have been in power. He also pointed to “the first time we’ve done gun control since President Clinton was here, the first time ever an African American woman [Ketanji Brown Jackson] has been put on the US supreme court.

“I think it’s a record to take to the American people.”

Klain’s references to historical figures chimes with Biden’s own interests. The president has regularly consulted historians, among them Doris Kearns Goodwin, Michael Beschloss and Eddie Glaude Jr, while Jon Meacham, a biographer of Thomas Jefferson, Andrew Jackson and George HW Bush, has been a close adviser in shaping Biden’s effort to restore “the soul of the nation” after the presidency of Donald Trump.

Democrats control Congress by narrow margins. Opposition parties commonly do well in the first elections of a presidential term, and Republicans remain favoured to take control of one or both chambers. But legislative successes, most recently the passage of a major domestic and climate crisis spending plan, the Inflation Reduction Act, have given Democrats hope.

One senator, Brian Schatz of Hawaii, pointed to the need to communicate better, writing: “I feel like the media is having a hard time metabolising the fact that this Congress has been historically productive. And acknowledging the size of these accomplishments, and the degree of difficultly – it’s just hard to do accurately without sounding a bit left-leaning.”

There is some indication that Democrats are becoming more popular. They have established polling leads in key Senate races including Arizona, Pennsylvania and Ohio, against Trump-endorsed Republicans who are struggling to attract moderates and independents.

In Kentucky on Thursday, Mitch McConnell, the Senate Republican leader, seemed to downplay expectations. McConnell said: “I think there’s probably a greater likelihood the House flips than the Senate. Senate races are just different – they’re statewide, candidate quality has a lot to do with the outcome.

“Right now, we have a 50-50 Senate and a 50-50 country, but I think when all is said and done this fall, we’re likely to have an extremely close Senate, either our side up slightly or their side up slightly.”

In his Politico interview, Klain said: “Elections are choices, and the choice just couldn’t be any clearer right now.

“Democrats have stood up to the big special interests. They stood up to the big corporations and insisted that all corporations pay minimum taxes, stood up to the big oil companies and passed climate change legislation. They stood up to Big Pharma and passed prescription drug legislation. They stood up to the gun industry and passed gun control legislation.

“Things that [Washington DC was] unable to deliver on for decades because the special interests had things locked down, Joe Biden and his allies in Congress have been able to deliver on.”

Asked about the Republican counter-offer, he cited issues Democrats hope can galvanise voters, prominently including attacks on abortion access after the supreme court overturned Roe v Wade, the ruling which protected the right.

“We have an extreme Maga group in the Republican party that has no real plan to bring down inflation,” Klain said, referring to Donald Trump’s campaign slogan, Make America Great Again. “They obviously want to pass a nationwide ban on abortion. They sided with big pharma. They sided with the climate deniers … most of them sided with the gun lobby.

“And so I think that choice [is] between a party that’s standing up to the special interests and delivering change and … an extreme party, a party that’s talking about … abolishing social security and Medicare every five years.

“The extreme nature of our opponents, whether it’s with regard to democracy or social security, are all part of a movement that is just very different than we’ve seen in recent years in this country.”

Klain said the worst day of the presidency was 26 August 2021, when 13 US service members were killed by a suicide bomb during the evacuation of Kabul.

That, he said, was “just a terrible tragedy and certainly the darkest day”.

Questions have been raised, including by Democrats, about whether Biden is too old to run for a second term. Klain said Biden’s experience – he will turn 80 in November – helped make him an effective leader.

Biden, he said, has “a personal history of tremendous, joyous successes and devastating tragedies. And I think that helps moderate his spirit at all times.

“There is nothing I can ever walk into the Oval Office and tell him that’s any bigger than the bigger things he’s already experienced in life. And nothing I could ever tell him is any sadder than the saddest things he’s already experienced in life. And I think that gives him a very level temperament as president.”

Klain was also asked about complaints, particularly from Republicans, that Biden does not maintain a high public profile.

“I don’t think it’s true he’s out there less than his predecessors,” Klain said. “I just think Donald Trump created an expectation of a president creating a shitstorm every single day.”