Don't like Clinton or Trump? Don't blame them.

If Donald Trump and Hillary Clinton secure their respective presidential nominations, they would become two of the least popular major-party nominees of the past quarter-century. And part of the reason, experts say, is a new reality of American politics: Voters seem to not just dislike specific politicians anymore, they dislike politics in general.

In an analysis of election-year polling data since 1980, the awards for the highest “strongly unfavorable” ratings among major-party presidential candidates go to Mr. Trump – at a stunning 53 percent – and former Secretary of State Clinton, at 37 percent.

The trend also suggests that strongly-unfavorable ratings are becoming more common since the turn of the century. No. 3 in the tracking is George W. Bush in 2004, who notched 32 percent.

So what is behind this unprecedented unpopularity of two presumptive presidential nominees?

A major factor is the candidates themselves, experts say. Trump and Clinton are magnets for criticism in distinct ways, from Trump’s brand of fractious populism to Clinton's long and controversial political history.

But the two candidates are also commanding the spotlight in at a time when increasing polarization is dramatically shaping how voters view the entire political process.

“People used to trust the government,” says Shanna Pearson-Merkowitz, a political scientist at the University of Rhode Island. “They have had a trust in American government as whole to do what’s right, and that’s what’s really changed.”

Not in the 1950s

The trend lines are well-known and long-term. Only 19 percent of Americans say they can trust the federal government to do what is right “just about always” or “most of the time,” according to a November 2015 survey from the Pew Research Center, down from 73 percent in 1958. Meanwhile, political polarization has increased, with the electorate becoming more hardened into liberal or conservative camps, and political parties increasingly hostile toward each other.

But the rise of Trump, paired with Clinton’s inability to pull away from Sen. Bernie Sanders in the Democratic primary, illustrates how polarization and disaffection have come to a head – embodied in presumptive nominees with historic unfavorability.

“[Voters] with the lowest trust in government, they’re picking outsider candidates not because they’re ideologically extreme, but because they’re bucking the establishment,” says Professor Pearson-Merkowitz.

“The big support for both Sanders and Trump is not based on ideology at all,” she adds, “it’s trust in government.”

This week’s Democratic primary in West Virginia highlighted that. Fewer than 20 percent of Democratic primary voters in the state identified as “very liberal,” according to The Washington Post, yet Senator Sanders – a self-proclaimed democratic socialist who has been further left than any presidential candidate this election – won handily. He even won over half of Democratic voters who said they want the next president to be more conservative than President Obama.

“The bottom line,” wrote the Post’s James Hohmann, “is most people are not voting for [Sanders] because he is liberal. They are voting for him because they perceive his promised ‘political revolution’ as a challenge to the system that has failed them.”

While the increased polarization makes most voters unified in disliking the opposing party’s candidate, the increased disaffection makes some voters dislike the candidate they may be most aligned with ideologically.

“If Trump and Clinton’s strongly unfavorable ratings were simply a byproduct of polarized politics, you’d expect them to have high ‘strongly favorable’ ratings too,” writes Harry Enten for FiveThirtyEight. “They don’t.”

Partisanship's long shadow

This disaffection is also apparent in the rise of independents, who now make up almost 40 percent of registered voters – more than Republicans or Democrats, and the highest proportion in more than 75 years, according to Pew.

Research shows that these independents are not less partisan than party members, they just want to distance themselves from the negative stigma associated with partisan politics. 

“Associating oneself with partisan anger, stubbornness, and inflexibility does not seem like the best way to make a great impression,” said political scientist Samara Klar to The Washington Post.  

“On the other hand, being independent and above the partisan morass seems much more impressive,” added Professor Klar, coauthor of the book “Independent Politics.” “People behave in ways that they perceive to be socially desirable and that cast them in the most positive light.” 

Indeed, the 1950s-style faith in government as a force for good in American life seems to have largely disappeared.

“The New Deal era, and for the politicians following that, it was about what the government can do,” says Pearson-Merkowitz.

What changed? Many things, including controversy over the Vietnam war, the Watergate scandal, and a burgeoning media industry to put government under scrutiny.

Pearson-Merkowitz also points to rising revolt, especially on the political right, against big government. “Now for the past 30 years it’s been all about, ‘We need to shrink the size of government because government’s dysfunctional.’”

“And it’s just been heightened and heightened over the years to the extreme where elected officials are saying, ‘Shut it down, I don’t agree to anything, just shut it down.’ And we’ve seen it shut down,” she adds.

Trump and Clinton might be extreme examples, but they're just part of a broader trend, says Geoffrey Skelley, a spokesperson for the Center for Politics at the University of Virginia.

“There’s a strong chance this is something politicians will have to deal with going forward.”