Speaking to hundreds of party faithful in Maryland, just outside Washington, Biden sought to build on growing energy in the party, which believes it can fend off a threatened Republican victory in the November 8 vote - labeling their rhetoric as "semi-fascist".

Casting the Republicans under ex-President Trump's sway as a party of "anger, violence, hate and division," Biden said, "We've chosen a different path forward: the future of unity, hope and optimism."

"This fall there will be a choice between these two visions. We must take our case to the American people and be crystal clear about it," he said, after likening Trump's Make America Great Again or MAGA brand as "extreme".

"It's not just Trump, it's the entire philosophy that underpins the -- I'm going to say something, it's like semi-fascism," Biden said.

'Literally save democracy again'

Just weeks ago, Democrats were in the doldrums.

With Biden's approval ratings below 40% and the party seemingly unable to close the deal on a series of election vows, there were widespread expectations that the Republicans would easily take control of at least one chamber of Congress.

A dramatic August, however, has sown the seeds of what some Democrats hope will be a political miracle, with their party holding the Senate and at minimum mitigating the size of the Republican win in the House of Representatives.

The Maryland rally came on the heels of a spate of legislative wins in Congress, coupled with fury among many Americans over the conservative-dominated Supreme Court's ruling to end automatic nationwide abortion access rights but Biden warned that Republicans would seek to outlaw abortion completely if they control Congress, saying the issue was galvanizing "the powerful force" of women voters. 

"You need to vote to literally save democracy again," he then said in his speech. 

He cited the racking up of laws on funding high-tech investment, the green economy, health care, and also a limited, but still politically impressive approval for new gun safety restrictions. His latest move on Wednesday announced that millions of voters will be eligible to have between $10,000 and $20,000 canceled from their often crippling student debt -- a longtime demand from Democratic supporters.

"Even our critics have been forced to acknowledge real progress," he said as the crowd cheered.

By contrast, Republicans have become distracted by drama over Trump's dispute with the Justice Department and the FBI over his illegal removal of classified documents from the White House to his Florida residence in Mar-a-Lago. 

Shifting polls

One reason the Republicans were expecting heavy wins in the midterms is that opposition parties nearly always punish the President's party in midterms, with the other being that Biden, after a tough year marred by repeated Covid variants and the highest inflation in 40 years, is quite unpopular. His average approval rating has been stuck below 40% since late June, making him as unpopular as Trump before him. The democratic party was even accused of "political malpractice" by one of Biden's own. 

Republican party leaders were predicting a "red wave" to sweep "blue" Democrats away as the redistricting of House seats was believed to favor the Republicans and effectively almost guarantee them several extra seats. However, now there's talk on the left of a blue riptide washing back in the other direction.

The average of baseline polls asking which party should control Congress has shifted from months where Republicans led to a narrow 44-43.6% advantage for Democrats.

In the individual races, there are also hints of hope for Biden's party, when a Democrat won Wednesday in a special election in a House swing district in New York - exactly the kind of district Republicans would expect to flip in a red wave.

The Senate, which Democrats currently only control with one vote, was also thought to be leaning toward Republicans, but even Republican Senate leader Mitch McConnell says that's now a 50-50 proposition, adding, "I think there's probably a greater likelihood the House flips than the Senate."

The veteran insider cited the "quality" of his party's Senate candidates - a clear jab at some of the Republican contenders chosen in large part because of their populist, pro-Trump credentials, rather than credibility with the electorate at large.

Meanwhile, Biden's own polling, while still terrible, is also creeping up as a Gallop poll on Thursday showed 44% approval, his best result in a year. By comparison, this is actually better polling for an August before midterm elections than Trump in 2018 or Barack Obama in 2014, Gallup said.

With the Democrats' already-growing dissatisfaction with Biden aside, members of the party are getting even more frustrated with how Biden is responding to the challenges that America is facing. 

Read more: Biden risks impeachment if Democrats lose midterms