As the Republicans' internal battles over the presidential nomination have quieted down, and will likely continue to simmer now that Donald Trump has crossed the threshold of delegate support, the war within the Democratic ranks has surprisingly intensified.

"For the last week it's been a game of opposites where Democrats have been behaving like Republicans and Republicans behaving like Democrats," said Ron Bonjean, a Republican strategist.

The ranks of the NeverTrumpers — those vocal prominent conservative writers and politicians who have vowed that they will never support Trump as a candidate — may be dwindling.

With former Trump-hater Senator Lindsey Graham now reportedly reaching out to donors to support the real-estate mogul, it seems that many Republicans, albeit some reluctantly, are unifying behind the presumptive nominee.

In the last week, presidential nomination contender Bernie Sanders has ratcheted up the rhetoric against his own Democratic Party. (Matt Rourke/Associated Press)

Not so with the Democrats. While Hillary Clinton will almost certainly win the Democratic nomination, her rival Vermont Senator Bernie Sanders and his very passionate supporters have revved up their political fight.

'Gotten angrier and more fiery'

"It seems to me he has gotten angrier and more fiery and more confrontational at the point at which you would have expected him to ratchet down the rhetoric," said political analyst Stuart Rothenberg, founder of the Rothenberg & Gonzales Political Report.

"I think it's a war because there are deep feelings, there's animosity on Sanders' part. He continues to throw rhetorical bombs and complaints and challenging the fundamental unfairness of the system."

There had been initial media reports that this battle had escalated into violence on May 21st at the Nevada Democratic convention and that some Sanders supporters began throwing chairs at the event. Those reports were later discredited.

However, tempers certainly flared at the convention ​and Sanders backers shouted down the keynote speaker, Senator Barbara Boxer, and others they thought were tilting the rules in Clinton's favor.

The state party responded by filing a formal complaint against the Sanders campaign with the Democratic National Committee, worrying that physical altercations could occur at the national convention this summer in Philadelphia, the City of Brotherly Love.

Republican Party members, even those once skeptical of Donald Trump, are rallying behind him. (Brennan Linsley/Associated Press)

In a statement, Sanders said he condemned "any and all forms of violence", but decried the Democratic political process in Nevada, writing that the "Democratic leadership used its power to prevent a fair and transparent process from taking place."

"If the Democratic Party is to be successful in November, it is imperative that all state parties treat our campaign supporters with fairness and the respect that they have earned," he wrote.

Meanwhile, Sanders has made no effort to conceal his contempt for Democratic National Committee chair Debbie Wasserman Schultz, accusing her of having rigged the system in favour of Clinton, who he says is her preferred candidate.

'I think the fighting has become very bitter in the last week or so and I think the reason it's getting worse than getting better is that we've got to the point where the Sanders people realize [Clinton] is going to be the nominee," said Brad Bannon, a Democratic strategist. "And because of that they're frustrated and angry and striking out."

While they may be frustrated that Sanders appears doomed to defeat, there are also a lot of deep feelings and anger among the Sanders supporters that they have been marginalized and taken for granted by the party establishment.

"And when you have the head of the DNC openly aligning with Hillary Clinton and telling Sanders to get his people in line, that's like throwing gasoline on the fire," said Bonjean.

DNC chair could be sacrificed

The immediate fallout from all this means that Wasserman Schultz's days as party chair could be numbered as she's sacrificed as part of the reconciliation process between the the Sanders and Clinton camps.

But these ongoing fissures may have given a decided advantage to Trump and possibly have implications come November.

Bannon, the Democratic strategist, said the party was fractured in 1980, when Ted Kennedy unsuccessfully challenged Jimmy Carter as presidential nominee. Carter was unable to heal the divisions, which was at least one of the reasons he lost to Ronald Reagan, Bannon said.

Although he believes Sanders and Clinton will publicly make nice at the party convention, this battle may give a decided advantage to Trump.

Will Bernie Sanders' supporters stay home on election day or rally behind Hillary Clinton? (John Locher/Associated Press)

"If that continues through to the convention, that means Trump has a two-month head start on making nice with the Republicans who don't like him," Bannon said. "So I think the same thing will happen on the Democratic side but the problem is it should be happening now."

And if peace is not made, many of the younger voters caught up in the so-called Sanders revolution may decide to stay home on election day and refuse to support Clinton.

"She needs a good turnout of them and needs to win them solidly," Rothenberg said, noting that recent polls show she's barely squeaking out an advantage over Trump.

At least some Sanders supporters, feeling left out of the process, could be potential recruits for Trump. In Clinton's 2008 race against Barack Obama, most of her supporters, although harbouring a lot of hard feelings, still decided to line up behind the eventual president.

"It's any guess where [Sanders supporters] will go. They are definitely not enthusiastic today and may not be when November comes around," said Bonjean.