In a heated debate Monday, Sen. Bernie Sanders (I-Vt.) and Republican challenger Lawrence Zupan gave voters a clear sense of the gulf between their political views.

Zupan repeatedly slammed Sanders’ brand of democratic socialism and said Sanders supports the kinds of policies that led to North Korea’s dictatorship and Venezuela’s failed economy. Sanders dismissed the attacks and accused Zupan of echoing national Republicans.

The debate, jointly sponsored by Vermont Public Radio and Vermont PBS, covered a wide range of hot-button political topics, and the two candidates agreed on almost nothing.

Sanders responded to a question about the convoy of people walking through Mexico toward the United States by restating his support for comprehensive immigration reform and the Deferred Action for Childhood Arrivals program, also known as DACA.

Zupan said he sees the convoy as an incursion.

“I’m asking who’s behind that, first of all — and what is the government of the United States supposed to do when there’s an organized invasion of the country’s borders?” Zupan said.

People living without legal status in the U.S. should be forced to leave and then apply for residency, he said.

If elected, the Republican real estate broker's first move on immigration, he said, would be to “secure the border so that we could stanch the flow of blood, so to speak.”

Zupan repeatedly dodged questions from moderator Jane Lindholm about whether he agrees with established science that climate change is primarily caused by human activity. Zupan insisted that his push for smaller government and less regulation would foster enough innovation in the energy industry that carbon-heavy fuel sources would become a thing of the past, rendering the cause and severity of climate change an "academic" point.

“I have the same goals,” he said. “I have a pink pair of lungs that breathe air.”

Sanders emphasized that he agrees with established science and said he was “scared to death” by a recent report that says problems caused by climate change will become severe more quickly than previously thought.

The candidates were similarly divided on the issue of abortion.

After Sanders stated his support for women’s right to choose, Zupan countered with a question: “How far outside a mother’s womb does the baby’s skull have to be before you would forbid … the doctor from puncturing its skull and vacuuming out its brain?”

Zupan didn’t directly state whether he believes women should have access to abortions, instead discussing larger inequities between women and men in the health care system.

Both candidates initially seemed to agree on one issue: Each stated support for legal protections for transgender Americans.

Then Lindholm followed up by noting that the question was related to President Donald Trump’s recent call to remove a legal definition that protects transgender people. At that point, Zupan wasn’t so sure transgender Americans deserve legal protections.

“This is a complicated question that deserves a lot of study, because it’s clear ... that people are usually born one gender or another," he said. "What is the cost to society of having a third gender?”

Zupan repeatedly cast Sanders as advocating for socialism, which he views as a malicious and corrupt ideology. Zupan said Sanders’ campaign rhetoric was a “reinvention of the word ‘revolution’ to describe the post-Marxist ideas where government takes over everything and redistributes it."

Sanders responded by accusing Zupan of echoing attacks Republicans made on the national stage.

“These are my thoughts,” Zupan replied.

“Well they’re pretty pathetic thoughts,” Sanders snapped.

Sanders and Zupan will face off again Monday evening in a debate sponsored by Burlington’s Channel 17. In that contest, the two will be joined by the seven other candidates running for U.S. Senate: independents Folasade Adeluola, Russell Beste, Bruce Busa, Edward Gilbert Jr., Brad Peacock and John Svitavsky, along with Liberty Union nominee Reid Kane.