Standing on the snowy lawn in between Burlington's City Hall and Main Street on a 20-degree January night, Theresa Fassett says things are going to get ugly.

"A lot of people are upset. There's a lot of anger, and definitely frustration," Fassett says, noting that she isn't typically involved in politics. "We have worked so hard for our entire lives -- since we were kids! And we have gotten nowhere. We are living with family. This is not the way this country is supposed to be."

In this two-part series, RealClearPolitics examines the angry voter, whose vast numbers in the 2016 presidential election are shaping the discourse -- and quite possibly will affect the outcome. Part 1 looks at what they are angry about. In Part 2, which will appear Tuesday, RCP looks at which candidate these angry voters might choose.

Standing beside Fassett on that cold Vermont night, Herman Merrill Spencer agrees. "People are sick of politics," he says. "People are sick of politicians doing absolutely nothing and stealing our money."

If they weren't each holding "Bernie 2016" signs, it might have been difficult to distinguish them at that moment from many of the people in the theater on the other side of Main Street.

"I've worked all my life -- grew up poor and hungry, and had to go learn to hunt at a very young age," says Kathy Robinson, a "seventh-generation Vermonter" wearing both a sweatshirt and baseball hat that bear Donald Trump's name.

"It's frustrating when I work 47 hours a week and I can't even afford health care," she says, taking her seat in the Flynn Center for the Performing Arts, where Trump was about to address a capacity crowd of 1,400. "I'm looking forward to change. I'm sick of politics -- which is one of the attractions of Trump. It's the whole political game. It's like, the money behind it is buying whoever."

Spencer and Fassett stood outside the theater for two hours to voice support for Bernie Sanders and to protest Trump. (The GOP frontrunner’s populist message was appealing to them in the beginning, but his inflammatory rhetoric, they said, turned them off.) Robinson waited in line in the cold for hours to see the candidate she believes embodies "the change we are looking for."

Trump's rise, Sanders' ability to exceed expectations in the Democratic race, and the interest, however fleeting, in other so-called "outsider" candidates have shone a spotlight on voters upset with the status quo. Polls and reports throughout last summer and into the fall and winter have exposed an anxious electorate, with a majority of Americans feeling the country is on the wrong track.

With voting set to begin in just a few weeks, these sentiments could be all the more consequential. While the Republican Trump and the Democrat Sanders tapped into tthis mood early on — albeit in very different ways —several other candidates have also picked up on it as well. The profile of the angry voter has made its way into stump speeches from Iowa to New Hampshire and on the two parties’ debate stages.

"People feel left out. They feel left behind. The economy no longer works for them," Marco Rubio said while opening a town-hall gathering in the Granite State. "We are no longer seen as the power we once were on the global stage. The world seems to be getting more dangerous and we are getting weaker."

Polling, candidate speeches, and comments from voters paint a picture of Americans increasingly cynical about politics, unhappy that so much money is spent on campaigns with little in return. While there are signs of economic improvement -- the unemployment rate is at just 5 percent -- voters remain anxious about their own financial security. And in the wake of the Paris attacks and the terrorist shooting in San Bernardino, Calif., voters are concerned about their own safety.

A recent Esquire/NBC News poll finds 49 percent of Americans say they have gotten angrier about current events and the news over the past year. Among them, 54 percent are white. Republicans are angrier than Democrats, 61 percent to 42 percent, the survey found. More than half of the respondents believe the American dream isn't attainable, and over half say their financial conditions haven't improved the way they imagined.

A Pew Research Center poll in late November found anger directed at government. Perhaps not surprisingly, Republicans were angrier in this regard than Democrats by a nearly 3-to-1 margin.

A USA Today/Suffolk University poll last month found a vast majority of Republicans saying the country is on the wrong track, while most Democrats see the United States heading in the right direction. The survey also found that Democrats value experience in their next president while Republicans value outsider status when it comes to making that choice.

In late September, an NBC/Wall Street Journal poll found that a plurality of respondents -- 44 percent -- were angry at the political system they feel works only for wealthy and powerful insiders, instead of helping ordinary people to get ahead. Twenty-eight percent felt anxious and uncertain about their own economic situation. Twenty percent felt neither.

The frustration with the political system is apparent on the campaign trail. In addition to raising questions about the economy and national security, particularly how to defeat ISIS and keep people safe, voters invariably bring up the idea of a broken political system and take issue with the amount of money spent in politics.

"Campaign finance is probably the biggest problem. It creates corruption," said Richard Helman after a Rubio town-hall event in New Hampshire. Helman drove there from West Virginia with his wife just to spend five days attending various candidate appearances.

"The way these candidates have to make so much money -- and the compromises they have to make to do it," he said, noting that he is leaning toward voting for Rubio or John Kasich. "My feeling is frustration with a broken political system in Washington. I think that's why Trump has such appeal."

Both Trump and Sanders eschew the super PACs their rivals have working for them, and often boast about the freedom and benefits that stem from being independent. Sanders has kept remarkable pace with his chief rival, Hillary Clinton, in terms of fundraising, and his contributions are notably from the grass-roots donors. Trump often plays up the fact that he is funding his own candidacy (though the campaign has been accepting donations).

"I like the fact that he is outside of the Washington circle, and he speaks his mind," said Peter Reiss, a pilot from Hudson, N.Y., who drove three hours to Vermont to see Trump. "I don't necessarily agree with everything he says," Reiss added, but no other candidate is speaking to his own concerns the way Trump is. "I'm upset. Distressed. I'm really, really worried about the future of this country."

Despite such commonly expressed sentiments, the term "angry" has taken on something of a negative connotation among those who hold these views. Many voters interviewed by RCP were reluctant to use the term, for fear of stereotyping.

"I don't want to use the word ‘angry.’ I don't like the term ‘angry.’ We are intellectuals," said Alan Grout, also of Hudson, N.Y. Grout wore Trump buttons on his hat and is an avid supporter of the billionaire real estate mogul, but he made a point to note he has a doctoral degree to underscore that supporters aren't just non-college-educated whites, as polls suggest.

"Anger doesn't improve the situation. Anger is more destructive than it is reputable," he said. "I'm not angry. But man, I want change. I want improvement."

Brenda Flower and her husband, Darren, also made a point to say they are "not angry. We are not angry Republicans."

"It's frustration. He's bringing common sense," Flower said of Trump, noting she has been a supporter of his from the beginning of the campaign. "We've always been Republican. But we are frustrated with the Republican Party right now."

"It's bad. Things are bad. I'm not happy," says her husband. "I'm not happy with the establishment. They just want their jobs, and then they do nothing."

When asked who or what was the source of their anger or frustration, Republican voters interviewed by RCP frequently cited the Obama administration and Congress.

“This is where the anxiety that permeates America comes from today. This is where the anger that permeates so many of our voters in America comes from today,” Chris Christie said during a speech in New Hampshire recently, referring to the administration.

"I rant and rave around the house every time Obama comes on. And Hillary," said one New Hampshire woman who attended a Rubio town-hall gathering and is leaning toward voting for the Florida senator. "The United States is becoming the laughing joke of the world."

"I think Trump is saying a lot of the things people are feeling, but he doesn't have a filter," she said, asking not to be named. "He is offending people. But he is saying a lot of things people have got going here," she said, pointing to her head.

Sanders supporters direct their fingers at current lawmakers -- excluding the Vermont senator, whom they view as non-establishment -- and the super wealthy, whom they don't think are taxed enough.

"I bust rock for a living. My lungs are shot after one season of busting rock," says Spencer, the Sanders' supporter standing outside in the snow last week. "And most of the money that generates from what I do goes to all the rich people. I do all the work, and they collect all the money. And I pay more taxes."

Both Trump and Sanders are interested in developing crossover appeal among each other's constituencies. And while they have different styles, they do overlap on a few policy stances, including opposition to free trade agreements and the super PACs.

"Many of Trump's supporters are working-class people and they're angry,” Sanders said recently on CBS' "Face the Nation." “And they're angry because they're working longer hours for lower wages; they're angry because their jobs have left this country and gone to China or other low-wage countries; they're angry because they can't afford to send their kids to college [and] they can't retire with dignity."

But Sanders said he is troubled by the notion that Trump has turned that anger about the system towards Mexicans and Muslims. "In my view that is not the way we're going to address the major problems facing our country."

Tuesday: Part 2 of this series examines which candidate the angry voter will likely choose.