When Mayor Pete Buttigieg argued at a presidential forum Saturday for a government-run health insurance option that people could buy into, while leaving the private industry intact, the crowd chanted "Medicare for All" so loudly organizers needed to tell the shouters to calm down.

It was one moment of several at the Iowa Citizens for Community Improvement forum during which Iowans sought to push Democratic presidential candidates toward more liberal positions Saturday. The forum only drew a relative handful of candidates, even as almost the entire field stopped by the Polk County Democrats' Steak Fry four miles away.

At the event, U.S. Sen. Elizabeth Warren of Massachusetts specifically declined to endorse national rent control. Former Secretary of Housing and Urban Development Julián Castro, faced a similar public option versus Medicare for All-style universal, guaranteed health care question. He only avoided the response Buttigieg experienced by qualifying his stance by adding he would make sure “everyone has Medicare who wants it.”

Only U.S. Sen. Bernie Sanders, whose 2016 presidential campaign shifted Democratic politics in a distinctly more progressive direction, received an overwhelmingly positive welcome.

"You did not eat any steak," Tom Rendon, with CCI, said in the event's closing remarks. "... That's what they're doing on the other side of town — they're practicing politics as usual. Here, we are practicing movement politics."

The Steak Fry brought 17 of the 18 major candidates currently in the presidential race, including all of those at the CCI forum. (Former U.S. Rep. John Delaney did not attend the Polk County event because he was at his daughter’s wedding.)

CCI, a self-described left-wing activist group, did not invite all of the candidates to their forum. The candidates needed to have answered a questionnaire sent earlier in the year and have met certain polling requirements. More than 2,500 people registered to attend the forum at the Iowa Events Center, a fraction of the 12,000 who had tickets to the steak fry.

The CCI forum was marked with cheers for questioners who pressed candidates toward more progressive policies than several had previously adopted.

Tiana Caldwell, an organizer with Kansas City Tenants, asked Warren to commit to the “Homes Guarantee,” providing 12 million housing units throughout the country, in addition to approving federal rent control laws. Warren highlighted her campaign’s housing policy, which would build 3.2 million new housing units.

When pressed, Warren did not commit to the specific policy about which Caldwell asked. Instead, Warren said she would work to prohibit state governments from wresting control away from local governments on the issue.

“What I want to make sure is that we aren’t prohibiting communities from developing the rent control plans for them," Warren said. "A rent control plan from Washington may work for Chicago, but it’s not going to work for Iowa City.”

Castro also would not commit to the Homes Guarantee.

“There are differences between what I understand the Homes Guarantee is and what my plan is,” Castro said. “I’m don’t want to sugar coat that. But I believe that mine is the most ambitious plan from any candidate has put forward.”

Castro was pushed on Medicare for All, a policy he does not support. While he said he wanted to improve and expand Medicare, he said he did not support legislation put forward by Sanders.

“I also want to be very straightforward with folks,” Castro said. “I believe we should set very strong standards and base our system off of Medicare with what I consider a private option. If someone wants to have a private health insurance plan, they should be allowed to have one.”

A few people in the crowd booed at that.

But Castro received a standing ovation for his response on changing immigration policies — such as making immigration courts separate from the Department of Justice.

Sanders, however, got an overwhelmingly warm reception. As soon as organizers mentioned their next speaker was “from Vermont,” the forum crowd was on their feet and cheering. It didn’t stop there: With almost every major line Sanders uttered, he was met with cheers — and at least one or two attendees on their feet.

“I love you so much that last election that I named a cat after you. So, no pressure,” Meggan Halverson from Committee for Better Banks told Sanders as she introduced a question on unionization.

The presidential candidate discussed many of his major policy proposals — “Free College for All,” Medicare for All and the Green New Deal — but also made familiar calls to build a political movement, referencing his campaign call of “not me, us.” The first question was how he would "co-govern" with groups like CCI.

"I'll tell you what no other presidential candidate will tell you: Not Bernie Sanders, or anybody else, can do it alone," Sanders said, as he often does from the campaign trail. "... The only way that real change has ever taken place, and will ever take place, is when millions of people stand up and demand justice."

Gene Foling, 62, said he came to the event as a Sanders supporter — and left feeling reaffirmed that the Vermont senator was the best choice for the presidency. But he said he enjoyed hearing the candidates answer tough questions from the organizers — and said that some candidates faced those questions better than others.

“Buttigieg — I would say he’s the loser on this one,” Foling said.

Buttigieg wasn’t “really a progressive,” the Sanders supporter said, which was why he faced more pushback from organizers at the progressive event. Foling, from Rowan, said while the event didn't change his opinion, the trip was worth it because he learned more about the presidential hopefuls.

“I still think Bernie is the better of the two progressives,” he said, between Sanders and Warren.

U.S. Rep. Ilhan Omar, D-Minnesota, the event's keynote speaker, made a similar call to action as Sanders: She told the crowd America needs to build a “permanent movement” in politics and think beyond 2020.

“We need a president who understands we are not fighting for just one election,” she said. “We are fighting for the very soul of our democracy and what society we want to become.”

Robin Opsahl covers political trends for the Register. Reach them at ropsahl@registermedia.com or 515-284-8051.

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