Organizers on Tuesday canceled next week’s Democratic primary debate in Colorado’s toss-up 8th Congressional District after former state Rep. Shannon Bird withdrew, leaving just one candidate planning to take the stage.

Three Democrats are seeking the nomination in the state’s June 30 primary for the chance to face first-term Republican U.S. Rep. Gabe Evans in what’s expected to be one of the most competitive U.S. House races in the country. Evans is unopposed in the GOP primary.

Bird, who had previously committed to the debate, decided against attending because primary rival state Rep. Manny Rutinel wasn’t going to be on hand, her campaign manager said. That left first-time candidate Evan Munsing, a Marine veteran and finance executive, as the only Democrat still participating.

The debate, sponsored by Colorado Politics, the Denver Gazette and the Common Sense Institute, had been scheduled to take place on May 20 in Fort Lupton in Weld County. Organizers had planned to stream the event on social media platforms.

While Bird and Munsing both confirmed their plans to participate in the debate in early March, neither Rutinel nor his campaign responded to repeated invitations.

On Tuesday morning, a Bird campaign spokeswoman told Colorado Politics that Rutinel’s absence meant her candidate also wouldn’t be there.

“We were excited to participate in this debate with all of the candidates,” Eve Zhurbinskiy, Bird’s campaign manager, said in a text message. “Unfortunately, because Manny Rutinel chose instead to host a DC fundraiser with the same big health insurance lobbyists driving up healthcare costs for all of us, we have decided not to participate in an event that does not feature the only other viable candidate in this race.”

Rutinel’s campaign last week began promoting a high-dollar Washington fundraiser hosted by U.S. Rep. Adriano Espaillat, a five-term New York Democrat and the chair of the Congressional Hispanic Caucus, among others.

Munsing told Colorado Politics he was disappointed that neither of his primary opponents wanted to meet for the debate.

“It’s incredibly frustrating that candidates don’t prioritize having real conversations, having debates, letting voters actually see the caliber of their thought as well as the content of their policies,” he said.

Munsing added that he believes his opponents are undermining Democrats’ plans to “hold Gabe Evans accountable” for declining to hold any public town halls since taking office.

“It sends a really bad message to voters that Democratic candidates aren’t willing to interact, be asked hard questions,” he said.

Colorado Politics editor Thelma Grimes, the debate’s lead organizer, said dozens of people had already reserved free tickets for the hour-long debate.

“These events provide a platform for all candidates to speak directly to the public, and for those not in attendance, to watch the video as they prepare to fill out ballots. In this case, it’s unfortunate to have a candidate withdraw only days before the event, limiting voters’ ability to hear from all participants and reducing the full exchange of ideas these forums are meant to provide,” she said in a statement.

Primary ballots start going out in the mail to most Colorado voters on June 8 and are due back to county clerks by 7 p.m. June 30.