Mayoral candidate Will Sandstrom was not welcome at a debate hosted by the Northside Business Association Tuesday.

Sandstrom, who was the only of the four candidates not to be invited, showed up the night of the event but was repeatedly asked to leave by the debate's hosts. According to Sandstrom, Mayor Dave Cieslewicz also asked him to exit the debate.

"I'd bet this is the only time in the history of the United States when a mayor running against candidates asks one of the candidates to leave," Sandstrom said.

When he tried to give his opening remarks, Sandstrom said event organizers and the mayor both said they would call the police if he did not agree to leave on his own.

But George Twigg, communications director for Cieslewicz, said the mayor had nothing to do with the event's guest list.

"It was the organizers that made those decisions about who to invite, who not to invite," Twigg said, adding Cieslewicz has been to many debates with Sandstrom and is always happy to have him.

Sandstrom, a retired biochemist, said the reason he was not invited to this debate was his religion — he said the event organizers were Catholic, while he is Protestant.

"It is obvious Catholics do not want any Protestants elected to public office," Sandstrom said.

Cieslewicz and Sandstrom are also facing Ray Allen, owner of Madison Times and former member of the Madison School Board, and Peter Muñoz, executive director of the non-profit Centro Hispano, in this February's mayoral primary.

Allen, who was at Tuesday's debate, questioned the fairness of excluding Sandstrom from the event.

"Let the guy speak," Allen said. "He got on the ballot — he has a right to say what he's going to say."

Robert Drechsel, professor of journalism at the University of Wisconsin, said there would likely be no legal issues with excluding Sandstrom from the debate, as the Northside Business Association is a private organization.

"Obviously, the organization can invite whoever it pleases," Drechsel said. "My view is always that — unless it's some unwieldy, large number that makes debate virtually impossible just because of the logistics — you would want to have all of the candidates present."

Sandstrom, who also ran for mayor four years ago, said this is not the first time he has been excluded from a debate. Sandstrom was not invited to a debate at a Madison Catholic church the last time he ran for mayor.

Following the Feb. 20 primary, two mayoral candidates will move on to face each other in the general election April 3.