For years, the Yimbytown conference was an ideologically safe space where liberal young professionals could talk to other liberal young professionals about the particular problems of cities with a lot of liberal young professionals: not enough bike lanes and transit, too many restrictive zoning laws.

The event began in 2016 in Boulder, Colo., and has ever since revolved around a coalition of left and center Democrats who want to make America’s neighborhoods less exclusive and its housing more dense. (YIMBY, a pro-housing movement that is increasingly an identity, stands for “Yes in my backyard.”)

But the vibes and crowd were surprisingly different at this year’s meeting, which was held at the University of Texas at Austin in February. In addition to vegan lunches and name tags with preferred pronouns, the conference included — even celebrated — a group that had until recently been unwelcome: red-state Republicans.

The first day featured a speech on changing zoning laws by Greg Gianforte, the Republican governor of Montana, who last year signed a housing package that YIMBYs now refer to as “the Montana Miracle.”

Day 2 kicked off with a panel on solutions to Texas’s rising housing costs. One of the speakers was a Republican legislator in Texas who, in addition to being an advocate for loosening land-use regulations, has pushed for a near-total ban on abortions.

Anyone who missed these discussions might have instead gone to the panel on bipartisanship where Republican housing reformers from Arizona and Montana talked with a Democratic state senator from Vermont. Or noticed the list of sponsors that, in addition to foundations like Open Philanthropy and Arnold Ventures, included conservative and libertarian organizations like the Mercatus Center, the American Enterprise Institute and the Pacific Legal Foundation.

“There aren’t many ideologically diverse spaces in American civil life at the moment, and one of the pillars of the conference was the idea of a big tent,” said Liz McGehee, one of Yimbytown’s organizers. “The more we can find areas of agreement, the more we can adjust to each other with less fear, and maybe that will help drive down the polarization.”

Housing, Framed Two Ways

As the lack of available and affordable housing has become one of America’s defining economic issues, it is increasingly a political problem. Politicians from both parties have found themselves inundated by constituents who have been priced out of ownership, forced into long commutes, and embittered by rising rents and multiplying homeless encampments.

Legislators in states including California, Minnesota, Montana, New York, Oregon, and Texas have reached for a similar basket of solutions. Invariably, they revolve around loosening zoning and development laws to speed construction, expanding renter protections for tenants and increasing funding for subsidized housing.

In plenty of places across the country — particularly blue states, where land use tends to be more heavily regulated — there is serious and organized opposition to these policies. Especially at a local level, voters have blocked developments of all sizes. (In many places, the divide over what to do about housing comes down to homeowners versus renters, rather than breaking along more typical political lines.)

And not all of these housing measures would be considered bipartisan. Republican legislators tend to be leery of price caps like rent control. Democratic legislators often push for streamlining measures to be paired with new funds for subsidized housing, for instance.

But since the highest-impact policies revolve around increasing the pace of building to backfill the decades-old housing shortage that is the root of America’s housing woes, there is still plenty of overlap. So much so that two frequently opposing think tanks — the American Enterprise Institute and the Progressive Policy Institute — recently hosted a joint event in Washington on increasing housing supply.

“Some issues become a horseshoe,” said Cody Vasut, a Republican member of the Texas House of Representatives’ Freedom Caucus, using a very Texas analogy. “We have different views of government but sometimes we arrive at the same conclusion.”

Housing has several features that make it an ideal issue for bipartisanship, said Jake Grumbach, a public policy professor at the University of California, Berkeley. Housing laws are hyperlocal and so don’t get much attention from national parties, which tend to push toward polarization. The subject is full of dense and wonky material that gets litigated through binder-thick planning reports instead of sound bites. It’s also hard to weaponize, since someone’s position on housing can be framed in ways that hew to either party’s ideology.

Take, for instance, the YIMBY mantra of allowing taller buildings and reducing the permitting hurdles to build them. Is this, as many Democrats say, a way to create more affordable housing, reduce neighborhood segregation and give low-income households access to high-amenity areas and schools?

Or is it, as Republicans say, a pro-business means of reducing regulation and enhancing property rights by giving landowners the freedom to develop housing?

Is it, somehow, both?

At this year’s Yimbytown, the message was that the political framing doesn’t really matter as long as you pass the bill.

Consider Montana, which last year passed a package of new laws that essentially ended single-family zoning by allowing backyard homes and duplexes on most lots in the state. Or Arizona, where a bipartisan group of legislators passed similar changes this week.

These laws followed, and in some cases were modeled on, state-level zoning changes that have already swept through legislatures in California and Oregon dominated by Democrats. To sell them in more conservative territory, advocates who had worked behind the scenes in Arizona and Montana gave tips to other Yimbytown attendees. They suggested hiring both liberal and conservative lobbyists and crafting pitches that lean into each party’s politics.

“We can focus on approaching a lot of the Republicans who are concerned about how zoning impacts property rights, how zoning is going to affect our communities and how they’re growing,” said Kendall Cotton, the chief executive of the Frontier Institute, a free-market think tank in Helena, Mont. “And then other groups that have connections on the left can talk to those folks about the climate change impacts of zoning, and building denser, more walkable cities, and the social justice end of it.”

In an interview after the panel, Mr. Cotton talked about one of housing’s most divisive subjects: single-family zoning, or laws that ban duplexes and apartments in certain neighborhoods and now define suburban character across large swaths of America. When legislators in blue states have moved to curb single-family zoning laws in the name of equity and the environment, conservatives have assailed them for trying to destroy what former President Donald J. Trump once called the “Suburban Lifestyle Dream.”

So when Montana tried to change zoning at the state level, advocates like Mr. Cotton took a different tack. To sell legislators on the plan, Mr. Cotton said he would pull out photos of cities like Missoula in the frontier days, when the streets were a jumble of one-room shotgun houses, duplexes and triplexes.

Today, like most of America, the city’s landscape involves a sprawl of subdivisions built around cars. How to revive the free spirit of that frontier past?

“END CALIFORNIA-STYLE ZONING,” according to a flyer Mr. Cotton distributed to Republican legislators, which also called for them to “Restore the right to build.”

A More Widespread Problem

Pitches like that one would have been unimaginable at the first Yimbytown eight years ago in Boulder, which was a glorified party of amateurs whose programming included an event at a beer garden where drunk people riffed about housing policy in haiku. This year’s conference had 600 attendees and featured a talk with Julian Castro, the former secretary of housing and urban development, a sign of the movement’s increasing professionalization and influence.

In the years between, as the YIMBY movement grew from a blue-city curiosity to a fund-raising and legislative force, the central conflict at Yimbytown remained the movement’s difficulty working with hard-left political organizations that have protested several events and view a “pro-housing” agenda as a progressive-sounding wrapper on trickle-down Reaganism. This continued in Austin: During the morning panel on the Texas Legislature, a group of protesters disrupted the conversation to assail the “pro-capitalist” speakers and chant “real affordable housing now” before being shooed out the door.

But when it comes to the brass tacks of moving bills, legislators from the right have turned out to be important partners. As the impact of rising costs has moved further up the income ladder and beyond a relative handful of tech-centric cities, Republicans in red states have become just as eager to show they are working on one of their constituents’ biggest problems. At the same time, many YIMBY groups have become focused on bypassing city councils and instead passing state-level legislation — which in most places is impossible without Republican votes.

“When you’re dealing with an issue that is as busted as housing is and where it’s affecting as many people as it is, you don’t really have the privilege of caring about what signal you’re sending,” said Henry Honorof, the director of the Welcoming Neighbors Network, a national umbrella organization for state and local YIMBY groups. “You care about getting something accomplished, and that means you have to be much more open to working with people that are often uncomfortable to work with.”

The conference was still an overwhelmingly center-left crowd, with panels on antiracism, building public housing and expanding tenants’ rights. But there was a sense among many attendees that they were building something distinct, a coalition with members from both parties.

Right or left, many of the conference attendees were young people in their prime homebuying years. They also tended to be people whose interest in politics was sparked by economic policy. Whichever party they identified with, they shared a collective belief that what America needs most is “abundance,” a new buzzword to denote a broader pro-growth mind-set of which YIMBYism is part.

“What’s so exciting is this supply side coalition that is emerging,” Mr. Cotton said. “There’s a group of people, Republicans and Democrats, who want to slow down growth — they’re preservationists, they’re protectionists. And there is the other side of things which says let’s build things again.”

Getting Things Done Quietly

Even so, many of the housing, climate change and social justice advocates who have long made up the bulk of the conference’s roster were deeply uncomfortable with the idea of sitting next to people whose name tags identified them as employees of conservative groups like Americans for Prosperity, backed by the Koch Network. Most refused to talk about their reservations on the record or publicly at the conference. They didn’t want to undermine red-state YIMBYs.

But in side conversations and at bar gatherings, they expressed their angst. YIMBYism is supposed to be about making cities more welcoming by reducing housing costs, one person pointed out, and wondered: If you work with a legislator to make housing more plentiful, then that legislator goes and votes for a law to prevent transgender people from using bathrooms, is that really welcoming?

The under-the-radar evolution in housing laws sweeping across the states is one of the few areas of policy where both the right and left can claim an ideological victory. And yet in today’s charged environment, winning with a partner you otherwise disagree with is often considered losing. Which is the reality both sides are worried they’ll one day have to grapple with, even as they quietly get things done.

“I have a great fear that land use and property rights will get coded left,” said Chance Weldon, the director of litigation at the Texas Public Policy Foundation, a conservative think tank in Austin. “That would be a tragedy, because we have been on the right side of this issue for a long time. But in a polarized environment, a lot of times people will support or oppose something just because of who’s attached to it.”