Tane Danger has been hosting the Theater of Public Policy for 350 shows in seven years, melding topical discussions with improvisational comedy.

For the first time Monday evening, he canceled mid-show after anti-pipeline protesters in the crowd continuously shouted down his guests, two utility regulators.

John Tuma and Dan Lipschultz, members of the Minnesota Public Utilities Commission (PUC), had been booked for the show at Bryant-Lake Bowl’s theater months ago.

But acrimony from a PUC meeting earlier Monday — in which the panel reaffirmed its support for a new $2.6 billion Enbridge pipeline across northern Minnesota — migrated to the small but sold-out theater in south Minneapolis.

The pipeline, a replacement for Enbridge’s aging and corroding Line 3, has been controversial. At the PUC meeting in front of a standing-room-only crowd, a few people did shout out their opposition after the vote but then left in an orderly fashion and protested outside.

But a September PUC meeting was cut short not long after protesters pulled out a bullhorn and castigated the commission over its June pipeline approval.

On Monday evening, Danger started the show with a quick introduction, a skit by the Theater of Public Policy’s players and then started interviewing Tuma and Lipschultz. As Tuma began explaining what exactly the PUC does, the hectoring started.

Lipschultz tried to pick up the conversation before cries of “they ignore the law” and “they break the law” were lobbed from the crowd. Danger tried to lower the room temperature.

“This place has a reputation for civil discourse,” Danger said. “There is a whole audience of people here that wants to learn from this.”

Most of the crowd of about 85 applauded. But shouting from a half-dozen people near the stage continued as Danger went on with the discussion.

“What about the pipeline you passed today?” one person shouted. “You are fired, you are fired,” another yelled at Tuma and Lipschultz. Danger tried more appeals to reason, saying “Do you think it will help shouting us off the stage?” One heckler yelled, “Yes.”

Not long after, Danger told the crowd: “I’ve never had to say this before, but we can’t go on with the show. I will refund your tickets. This is not what you signed up for.”

The show closed so early that Danger never got to ask Tuma and Lipschultz about Enbridge’s new Line 3, nor did the audience get to ask questions of the guests — the usual procedure.

The Theater of Public Policy, which Danger co-created with Brandon Boat, mixes serious policy issues with improvisational comedy. (The improv troupe didn’t get to do much either Monday.)

“We have talked about really hard things on the show before,” Danger said in an interview later. “I have had people ask, ‘How can you do a show about that?’ ”

A few weeks ago, he successfully did a show on the increasingly likely prospect of hard-rock mining in northeastern Minnesota — a topic every bit as contentious as Enbridge’s pipeline. The show pitted representatives of the anti-sulfide mining Minnesota Center for Environmental Advocacy and a pro-mining conservative think tank, Center of the American Experiment.

Environmental groups and some American Indian tribes have long opposed Enbridge’s new pipeline, saying it will open a new region of Minnesota’s pristine waters to degradation from oil spills, as well as exacerbate climate change.

Calgary, Alberta-based Enbridge has argued before the PUC for years that its aging and corroding Line 3 — which runs at only half capacity due to safety concerns — needs to be replaced.

After the aborted performance, Danger noted the bad timing between Monday’s PUC pipeline meeting falling on the same day as the show. On Monday, the PUC declined to reconsider its earlier approval and decided Enbridge had met several conditions the commission had imposed.

“They were passionate,” Danger said of shouters in the crowd. “And today was a day that made people who were passionate more passionate.”

Still, the show’s mission was quashed.

“It’s important to talk with each other with respect for each other as human beings,” Danger said. “I worry about civil discourse falling apart.”