When Joe Biden huddled with a group of historians in March, the conversation revolved around thinking big like one of his predecessors, Franklin Roosevelt, architect of the New Deal. Biden, it seemed, wanted to join him in the first rank of transformational US presidents.

Six months later, a very different gathering took place this week outside the White House gates. Five young climate activists, holding signs and sitting on folding chairs, began an indefinite hunger strike. It was a visceral expression of disgust at what they see as Biden’s willingness to think small and break his promises.

“Young people turned out in record numbers to elect him on his climate commitments,” said Nikayla Jefferson, 24, an activist helping the quietly determined hunger strikers on the edge of Lafayette Park. “But over this past month he’s almost given up. He’s not being a leader in this moment in the way that we need him to deliver.”

A growing sense of betrayal is shared by campaigners for everything from gun rights to immigration reform, from racial justice to voting rights, who saw Democrats’ governing majority as a once-in-a-generation opportunity. Instead party infighting has put Biden’s agenda in jeopardy and could result in voter disillusionment in next year’s midterm elections.

The 46th president came into office promising to attack four crises – coronavirus, climate, economy and racial justice – but has seen his approval rating sink to 42% after colliding with some harsh political and economic realities.

These include tepid jobs growth, labour strikes, rising inflation and petrol prices, logjams in the global supply chain, a record number of arrests at the US-Mexico border and a botched withdrawal of US forces from Afghanistan that raised unexpected questions about his competence.

Even routine business, such as appointing an ambassador to Japan, appears to have become jinxed: Biden’s choice for Tokyo, Rahm Emanuel, provoked a backlash from liberals because of his record on racial justice as mayor of Chicago.

Worries that Biden has lost his way have been intensified by his failure to hold an open-to-all press conference since taking office in January. In that time he has done only 10 one-on-one interviews – far fewer than Barack Obama or Donald Trump at the same stage.

But the biggest sense of a stalled presidency derives from seemingly interminable wrangling among congressional Democrats over Biden’s $1tn physical infrastructure bill and a $3.5 trillion social and environmental package.

Two senators in particular, Joe Manchin of West Virginia and Kyrsten Sinema of Arizona, have demanded cuts to the reconciliation package, prompting public acrimony with Senator Bernie Sanders and other progressives that has come to dominate Washington and crowd out other urgent causes.

Biden’s proud march into the history books appears to have descended into internal party mudslinging.

Jeff Merkley, a Democratic senator for Oregon, told the Meet the Press Daily programme on the MSNBC network: “It’s completely taking the air out of the balloon for the Biden presidency. It’s hurting Biden. It’s hurting the Democrats. It’s undermining the vision of all the accomplishments we will have as being highly significant.”

With his legislative agenda in limbo if not peril, Biden was this week forced to step in, host both factions at the White House and take a more aggressive role. This gave some Democrats fresh hope of a breakthrough but indicated that he will pare down the $3.5tn package in favor of a more modest proposal, threatening a clean electricity programme that was the centerpiece of his climate strategy.

It also underlined concerns that Biden is yielding to corporate interests on fossil fuels, prescription drug prices and tax increases. Critics say he has become so consumed with the grind of policy sausage-making that he has lost sight of big picture issues dear to his supporters.

Among them is the fate of democracy itself.

Last week Senate Republicans deployed a procedural rule known as the filibuster to block, for the second time, debate on sweeping reforms that would protect the right to vote. Activists who knocked on doors and raised funds for Biden warn that his failure to prioritize the issue above all others could prove his biggest regret.

LaTosha Brown, co-founder of Black Voters Matter, said: “Do I believe that he’s against voter suppression? Absolutely. Do I think that he supports voting rights? Absolutely. Do I believe that he is willing to use the full power of his office and his administration to ensure that voters that voted for him are not punished for voting for him? That’s yet to be seen.”

In a CNN town hall on Thursday night, Biden signaled support for filibuster reform. But he should have pushed the cause earlier and more forcefully, Brown argues.

“When you fight for those that fight for you, you go in the midterms with an advantage. I think they squandered that with choosing the wrong strategy. They miscalculated. Black folks may not have another real, viable party option but we always have options,” she said.

Derrick Johnson, president of the NAACP, a leading civil organization, described the White House’s passivity about safeguarding democracy as “appalling”. He told the Washington Post: “I have heard from many of my colleagues and members that the lack of priority around voting rights will be the undoing of the legacy for this presidency.”

Disenchantment was evident again last weekend when dozens of advocates for immigration reform staged a virtual walkout on administration officials during a video meeting. They are critical of Biden’s continuation of Trump-era border policies such as forcing migrants to wait in Mexico pending asylum hearings and deploying a public health order known as Title 42 to expel migrants at the border over concerns about Covid-19.

Ariana Saludares, an advocate from the New Mexico-based community organization Colores United, who took part in the walkout, said: “Title 42 is a sham. Politicians, including the current administration, use it to explain that those coming across the borders have higher rates of infection. We have the numbers from our shelters along the borders to show that that is absolutely false.”

Speaking by phone from Puerto Palomas, a small border town in Mexico suffering water shortages, Saludares asked: “Where is Joe Biden? Where is Kamala Harris? Where are all of these things they said that they would be able to provide us with after such a ‘horrible period’. And now what? It leaves a lot of people wondering what actually are they doing?”

The disappointment of grassroots activists spells trouble for Democrats ahead of midterm elections for the House of Representatives and Senate that historically tend to favour the party that does not hold the White House. Ominously seven House Democrats have announced they will retire rather than run for re-election, with another five seeking other elected office.

Democrats fear a replay of 2010, when the tortuous but ultimately successful passage of Obama’s Affordable Care Act did not prevent a crushing defeat in the midterms. And looming in the distance is Trump, who seems likely to run for president again in 2024, a prospect that fills many observers with dread for the future of American democracy.

Bill Galston, a senior fellow at the Brookings Institution thinktank in Washington and former policy adviser to President Bill Clinton, said: “This is obviously a delicate moment in the Biden presidency. Right now the Biden agenda is the equivalent of airplanes in a kind of a crush, circling above an airport that doesn’t have enough runways to accommodate all of them simultaneously.

“Things will look different once some of the planes begin to land and I do expect that the infrastructure bill and a pared-down reconciliation bill will in fact be enacted into law well before the end of the year. That will change the mood to some extent. The situation is not quite as bad as it looks – but it’s bad enough.”

But not everyone is doom and gloom. Antjuan Seawright, a Democratic strategist based in Columbia, South Carolina, was more upbeat. “I feel cautiously optimistic,” he said. “Joe Biden has demonstrated over time his ability to take a licking and keep on ticking. He’s also demonstrated that when people count him out, he always teaches them that they do not know how to count.

“When the ink dries about the story of this piece of history, you’re going to see that as the continued theme when it comes to Joe Biden. I believe we’re right where we need to be. Mike Tyson has a quote, ‘The key to being successful is peaking at the right time,’ and I think Joe Biden will in the end do just that.”